August 2006

Date Event


Wiring / Instruments

Time to turn my attention to the instrument wiring.  I dug out the photographs of the instrument wiring and labelled them up for reference.  I had kept the wiring loom and proceeded to wire up the new dash panel matching the connectors to the photograph. Almost the first problem I came up against was the old XJ6 instruments for fuel, oil pressure and water temperature, had different style connectors for +12v live feed (male) and sensor inputs (female). The new instrument from Carebont (Smith's Classic Range)  have only male connectors.   I devised a test circuit using  a 12v battery , 2 pieces of wire with connectors to match the instruments. I soldered a 72 ohm resistor in one of the leads.  I tested the circuit on the old XJ6 instruments  connecting one lead to the live feed and the other (containing the resistor) to the sensor connector. connect the live feed to the battery positive and the resistor to the battery negative. The gauge moves slowly up the scale. I repeated this test on the new instruments marking the +ve and sensor terminals with a marker pen. Once I new, for sure, which way round the instruments  were to be connected I connected the XJ6 instrument looms to the new dash panel. The XJ6 wiring loom has proprietary connectors on the end, that need to be replaced with connectors that match the XK120 wiring loom. I'm not using the built in warning lights for indicators. bulb failure, heated rear window  so these were left disconnected whilst I unravelled the loom and cut off the XJ6 connectors.   I removed all the redundant wing.  I had identified the instrument plugs in the wiring loom when I first laid out the loom and labelled them. Instrument connectors  #1 and #4 are the ones needed to connect to the instruments.  The task is to match the wiring loom colours to the instrument panel loom colours. (they are different).  The way I did it was to draw the wring loom connectors (viewed from the front) and mark each pin and the colour of the wire connected to it. I then matched the corresponding instrument or sensor wiring to the pin on the diagram (as viewed from the rear)   this way the pins and the wire match. I made up matching connectors  by connecting the shell  to the wiring loom and marking each with a marker pen so I knew exactly how they fitted together. I  soldered  pins to the end of the lead from the instrument panel and inserted them from the back into the correct position on the shell.  I found a mistake in  the listing of the connection for instrument plug #4 in my build manual. The listing  for  first connection runs over two lines which causes all the subsequent listings to be one pin out.  The listing should be follows.
white/black iGN negative  (tacho pulse sensor)
green/brown flasher unit
green +12v feed to gauges
brown/white oil pressure sensor
light green/white n/s indicator feed
red/white gauge illumination

 I still have to sort out gauge illumination and earth connections. Gauge illumination may be a problem because the original XJ6 instruments had green filters fitted to them but the new instruments do not.  It will look a bit incongruous with white lighting for the smaller gauges and green for the speedo and rev counter. 




I finished the wiring of the instrument panel today.  I still have to decide how I'm going to connect the indicator warning lights. These are included in the wiring of the instrument plus because the warning lamps were built in to he speedo and tacho instruments originally.  I suspect I'm going to strip the wiring out of the loom and connect them to the warning light panel via a new connector.   I spent the rest of the day stripping the correct coloured wires out of the XJ6 wiring looms to wire up the warning light panel.



Wiring / warning Lamps

Not much to say about the weekend.  I continued to work on wiring up the warning light panel.  During the weekend the soldering iron died, which kind of hampered things.  I may have pointed out earlier that though the male and female spade ends can be crimped in place I never seem to get a good neat looking crimp and I  prefer to solder them in place.  I was using the XJ6 warning light panel as a wiring guide which was proving useful even though the wiring colours were different from the build manual.  One point to note was that the battery / ignition warning light had 100 Ω resistor mounted between +12v and the charge line input to the lamp.  I surmise for two reasons.  The resistor will provide the alternator with a sensing path to +12v if the bulb fails  or the resistor will act as a pull up resistor to +12v ensuring the  lamp extinguishes as the alternator voltage increases. Either way I decided to incorporate it in to the warning panel I'm wiring up.  The problem was how-to mount resistor securely. In the XJ6 it was soldered to the printed circuit which made it pretty well secure.  I had some resistors with heat sink mounts that would have been ideal except they were of the wrong value. I thought about it for a while and experimented with terminal strips that could be secured to the panel without success.  Then I decided to butcher one of the heat sink resistors  to make a mounting. The resistors are epoxy glued in to the centre of the heat sink. It was a case of drilling out the resistor opening out the hole to accept the resistor from the XJ6 and epoxy glue it in place.  Job done, I left it overnight to dry. 

I soldered two flying leads to the resistor and covered the joints with heat shrink sleeving to insulate them. It doesn't matter which way round the resistor is connected but I chose white wire for one lead and white/black for the other, to match the circuit wiring.  I soldered flag type terminations to the end, I made the +12v connection and the charge light connection with 2 -1 piggy back connectors , this provided me with the extra terminals to connect the resistor in place.  I have made temporary connection to all the warning lights and have decided to gather these in to a short loom terminated in Mate-N-Lock connectors.  This will give the capability of removing the panel easily in the future, if necessary, by disconnecting the panel as a whole from the main loom.  I'm waiting for the extra connectors to come from Vehicle Wiring Products (VWP.)
 I've also decided to break out the connectors for the indicator lamps from instrument connectors #1 and  #4 and put hem in to their own Mate-N-Lock connector that will be connected to the warning panel wiring loom.




Today I spent identifying and marking the rest of the dashboard area wiring.  I've identified most things but still have a few connections I need to clarify with Nostalgia, to see if they are used or there has been some change in the wiring.   I also discovered, along the way, that I was supposed to have retained the starter relay and the lighting relay  from the XJ6.  Luckily, I had saved all the electrical wiring, switches and relays so it was just a case of identifying them.  Once again my photographs taken at the time I dismantled the XJ6 proved useful. In addition I've use the Haynes Manual for the XJ6 series III but in addition I have also used the Jaguar Heritage Museum (JHM) CD ROM for the XJ6 Series III (1979 - 1987). This latter publication also contains parts manuals electrical and mechanical information.  If you are using an XJS  as a donor,  the AJ6 engine or Getrag 5 speed box  I would also recommend the XJS 3.6 litre (  1982 -1991) CD-ROM from JHM .  The starter relay is a Lucas type relay, part #  C.36617, the headlamp relay part number is C.38616.




Brake Lights


Not all these hours were productive. I spent a long time on the brake light switch. I was aware that I had not fitted the brake light switch but I was prompted to do something about it by the wiring loom.  I spotted a diagram of it in the JHM CD-ROM when I was looking at the starter and Lighting relays information last night.  So I knew what I was looking for when I started the hunt through the boxes of XJ6 stuff I had kept.  It took a while but I eventually found it complete with bracket.  I spoke to Chris at Nostalgia to clear up the wiring I wanted identifying and ask where the starter relay and flasher unit should be fitted.  The answer of on the RHS of the bonnet hinge in the engine bay  now made sense of a why I had so much of the wiring loom in the RHS foot well of the  cockpit.  It needs to be fed across the bulkhead along the RHS  side of the bulkhead and in to the engine bay. Once there under the pedal box cover between the pedal box and the bulkhead. 

Back the brake light switch. I had completely forgotten how the switch fitted to the pedal and looking at my photographs must be one of the few components of the XJ6 I don't have a photograph of.  The JHM CD-ROM came ot the rescue. It mounts across the pedal box secured by 2x UNC bolts the fit in to 2 tapped holes in the webs that support the pedal pivot, in front of the pedal. It doesn't work how imagined at all. The switch is not a push on type but a push off type.  Because it is mounted in front of the pedal. When the pedal is pushed to apply the brakes the switch is released and makes contact switching on the stop lights. when the pedal is released it returns pressing the switch, opening the contacts and the stop lights go out.   I fitted the bracket to the pedal box and tested the switch operation,. Unsurprisingly, it needed adjusting for correct operation.  The switch is held in position by a single bolt and a keep plate. Loosening this bolt allows the switch to twist ,effectively moving the operating lever closer or further away from the pedal. Using a multimeter to check continuity across the switch and indicate when  the contacts opened  . closed. With the brake pedal released  I moved the switch to it's extreme position so that he contacts were made meter indicated the contacts were closed.  I slowly rotated the switch until the contacts opened as shown on the meter. I adjusted the switch a small amount further to make sure the contacts were firmly held open and tightened the securing bolt.   I checked the operation of the switch using the pedal. Just a light pressure in the pedal produced a small amount of movement and operated the switch. Releasing the pedal opened the switch.  Satisfied with the operating I removed the bracket and the switch and dismantled it to refurbish the bracket and clan up the switch.

I then set about rerouting the loom. I found the easiest way to do this was  to tape any  loose ends to the loom with masking tape so that they could not flap about.  I withdrew the main switch panel loom back to the main instrument panel area.  These have no preformed ends and will be easier to route later.   I passed the loom back up through the hole for the demister duct. There is a small hole in internal supporting bracket which I sued to get the loom in to the area above and to the right of the steering column. It's fiddly  work but it will go.  To the right of the steering column there is a large oval hole that you can get a hand in to assist with threading the loom and to feed the loom around and out in to the engine bay.  I found it useful in threading the last part of the loom in to the engine bay and around behind the pedal box  to work from within the wheel arch. There is just sufficient room to reach the end loom from within the wheel arch and pull it in to the wheel arch ,then thread the loom back between the bulkhead and the pedal box.  (to be continued tomorrow......)



Wiring Starter relay

I did not get a lot done yesterday. I finished threading the loom for the starter relay  and the flasher unit so that I could determine the position of the real and flasher unit on the bulkhead. I marked their positions on the bulkhead and drilled the hole next to the bonnet hinge for the starter relay I temporarily mounted the relay with a  #10 spire bolt. This enabled me to mark the other hole. Drilling this hole and the mounting hole fro the flasher unit was going to be difficult since the clutch reservoir was going to get in he way. I slept on it overnight to think about it.  Today I drilled the holes using a combination of  right angled attachments to the Dremel and short drill bits to drill 2mm pilot holes, followed by a 4mm drill in a flexible drive to open out the holes to self tapping size.  I examined the loom and connections for the starter relay  noting the change in colour of the inhibit wire. I need to do some meter checks to sort out the remaining connections because both the connection to the ignition switch and the solenoid are coloured White / Red and whichever wire goes to the solenoid doesn't look big enough. A job for tomorrow.

Having refurbished the bracket  mounting bracket I reassembled the brake light switch and fitted it,  finally adjusting it using a multimeter  as explained above.




Ignition / Starter


I began by testing the wires to the starter relay to determine which was which.  carrying out continuity tests with a digital multimeter I established which of the white/ Red wires was connected to the ignition switch , which meant the other one was intended for the solenoid.  The green/ white wire was the inhibit  switch (not used on manual cars) which I had identified earlier when sorting out the wiring in the region of the handbrake, but it did no harm to recheck. Brown was obviously the live feed.  I was concerned that the wire destined fro the solenoid was a little under size for he job. It was definitely smaller in diameter that the equivalent wire from the XJ6. Besides I couldn't readily identify where the other end was in the loom.  I had connected the XJ6 wire to the starter motor when I  fitted it to the engine. I decided on balance to use this wire in preference to the one in the loom. It was already covered in woven sleeving but I added some black PVC sleeving over the top as a further protection. I loosely dressed  it around the loom to the starter relay  to determine the approximate length required . Trimmed and soldered a new end on it,  I tied the inhibitor lead back in to the loom for safety and made a new earth lead to connect to the W1 terminal in its' place. I connected the wires and mounted the relay on to the bulkhead with 2x #10 spire bolts., using one of them to anchor the earth lead to the bulkhead. I checked for good continuity between the battery earth and the relay.  Whilst investigating the other leads that emerge from the wiring loom in this area I noticed a spur in the loom containing a brown( live feed) and q white / red wire. which turned out to be the missing other end of the solenoid wire from the starter relay. It is of no consequence since I decided not to use it. However I will need to find out where the +ve feed is intended to go.  

Starter Relay Connections

White Red (thin) W2
Green /White (auto only) inhibit W1 (Manual cars connect to earth)
White / Red (Thick) C1 (Starter motor solenoid)
Brown +ve Feed from strip fuse.

The next job was to fit the flasher unit. I identified the wires and corresponding terminals. The only problem here was there are 2x  green / brown  wires from the warning light circuit and only one connection on the flasher unit.  It was fairly easy to sort out a 2 in to one connector to connect them ot the flasher unit.  I was suspicious from the outset that the "stick on" mounting bracket would not be strong enough for the job, and so it proved. once the flasher unit was mounted on the bulkhead the weight and strain of the wires proved too much and it came unstuck.   I am not a fan of attaching wires direct to relays and flasher units I prefer them to fit in to a socket.  I decided to raid the XJ6 wiring loom. I found the flasher unit and liberated the socket from the loom. I extracted the terminals from the base with an extraction tool.  I extracted the terminals from their covers in the wiring loom.  I checked the new "Nostalgia" Flasher unit fitted  the socket base from the XJ6. The terminal pattern was different but it fitted the basic socket. It just needed the terminals fitted in the correct position for the new relay.  I fitted the terminals from the loom in to the socket all except the Green Brown lead. I need to get a new terminal so that both of them will fit the one pin.   I next made a relay mounting bracket  by modifying a bracket from the XJ6 . I drilled an mounted the bracket to utilise the hole I had already drilled in the bulkhead.  I mounted the flasher unit temporarily until I get he new terminal.

I finished off by mounting the headlight relay on the bulkhead behind where the instrument panel will fit. At the same time I rerouted the loom for the light and heater switches back to the RHS of  the bulkhead, That I disturbed when routing he starter relay and flasher unit looms.




Warning Lights

When I mounted the headlight relay last night I forgot to fit the suppressor that fits between the headlamp flasher (blue / black , 31b),  and Brown (+ve Feed , 81a).  It took just a few minutes to remove and the relay and fit it.

The  rest of the day I have worked on the warning light panel  I have fashioned the loom and more or less worked out the route to the instrument panel connectors.  I modified the wining loom to extract the flasher unit and indicator wires from instrument plugs  #1 & #4. I fitted these in to a new connector #5. The reason for doing this was to separate the connectors that supply the instrument panel from those that  service the warning light panel. I've formed the loom on the warning light panel and fitted the mate- n -lock connectors  making sure that the wires correspond correctly with the main wiring loom.






This morning started well with tidying up and re-looming ,as necessary, the branches of the main loom that connect ot the instrument  panel and making the connections from the lighting and  heater looms to the switches on the side panel. About mid morning  the parts arrived from VWP .   It seems I had ordered the wrong terminals for connecting to the flasher socket. Nothing for it but to go in to Newbury to the Auto Electric dealer and  get the correct ones.  Having returned with the correct terminals and made up the connections, I found I could not get it to fit if I had 2 leads connected together in the one terminal. It was simply a case of not enough space to insert the terminal the leads in to the socket.  I started to work on a solution. A single lead would do, but would it have the current carrying capacity?  If all the bulbs in the indicator circuits were on simultaneously it would come to a total of  88 watts. A current of 7.3 amps.  I set about identifying the current capacity of the green / brown wires in question.  I measured a strand of the wire as 0.3 mm and counted the strands in the wire as 28. Referencing  some data from VWP, the wires were capable of carrying 25 amps continuous, making a total of 50 amps capacity over he two wires.  It doesn't take a genius to work out the circuit is massively over engineered.  I could getaway with one of the wires connected to the flasher unit easily.  Using a piece of identical wire I made a connection that would fit the flasher socket and connect to bullet and snap connectors to join the two wires from the loom to the flasher unit.  I joined up the connectors and taped the snap connector in to the loom to finish it off.

I did two jobs in the afternoon.   I fitted PVC beading to the edges of all the holes in the box section at the top of the bulkhead, through with cables or pipes pass, to protect the loom from chafing.   The second job was to tidy  up and reroute the wiring for the power resistors and air meter unit. The chosen route was round the back of the pedal box and down the side between the pedal box nd the wing valence. though there is plenty of room there fro the cables, I'm having difficulty getting the meter unit connector down the side of the pedal box. I my have to take the  cover off or modify the wing valence to give me more room.





Bulkhead Routing

I decided modifying the wing valence was the preferred solution to my problem with the air meter unit wiring. Even if I had removed the top cover over the pedal box I still would had a problem of feeding the connector past the font casting of the pedal box.  I cut a small section off of the bottom of the wing valance, sufficient to give me enough room to feed the outstretched cable up between the pedal box casting and the valance.  This tidied up the ECU wiring loom quite a bit though it is still not secured in place . I will do this later.

Another problem I have been concerned about is the wiring passing through the holes in the upper box section of the bulkhead. Most of them I have lined the edges with PVC beading . However the RHS hole can only be reached from underneath the steering column and has all of the wiring for connecting to the ECU loom, flasher unit , indicator repeater, Starter relay, inertia switch and lighting switches passing through it.  I tried it but with all these wired going through it and limited access  it was impossible to get a an edge beading around it.   The solution looked like it needed a piece of split tube that would rap around the  cables and fit in to the hole securely ,making a rubber guide that would prevent the cables coming in contact with the edge of the hole.   As luck would have it  I fond a short length of rubber hose (Part No; AS1322- SNG Barratt) ) left over from the XJ6 cooling kit.  This was almost an exact fit to the diameter of the hole. I split it lengthwise with a sharp knife, wrapped it around the cables and pushed it through the hole up to about half way.  I made sure the spit was at the top so that it was in a area not in contract with the cables.  Once in place I wrapped cable tie around it to secure it  so that it could not come open.





Ignition switch


Wash Wipe Stalk



This  is accumulative time over the past 3 days since I returned from holiday in North Devon.  I've completed the changing of the XJ6 connectors for the steering column stalks and the ignition switch for ones compatible with the wiring loom.   There are some redundant wires in the ignition switch loom not use in the Classic 120. Brown (thin and Brown / Red for the anti run on valve  and Purple / Green and Purple / White for the door open alarm.  These wires were trimmed back and the ends covered with heat shrink sleeving and tied back in to the loom.  On my car there was change in wiring colour. The wire connecting to the Start Relay terminal C2  colour was given as White Red (Jaguar Loom) but was, in fact,  White / Yellow .

 The wiring for the wash / wipe stalk gave me a little trouble, I had 2x Lt Green / Black wires  which were not connected together. One was , supposedly, intended to be Black/ Light Green for the wiper speed 1 and the other Lt Green / Black the  washer button .  However it was very difficult to tell them apart.  To identify them I had to remove the stalk from the steering column and remove the wrapping from the loom.  Once the wrapping was off it became clear. the wire from the washer button had a join in it. The true lead colour was  LT Green / Black (spiral tracer, which removed the confusion. The connections were confirmed with a multimeter test. 

Excess loom for these connectors was pushed back in to the box section above the steering wheel.  Some final securing and tidying work still needs to be done.

I've connected the interior heater motor to it's connector in the loom.  The horn push connection is on the outer steering column about half way down on the RHS under the bulkhead box section.  I had to make a short adapter to between the loom and the snap  connector for the horn on the column.

Lastly I fitted the inertia switch. Nostalgia fit this switch up under the dash panel close to the windscreen pillar.  I wanted to make the switch more easily accessible in case it should operate accidentally and needed to be reset.  ( unlikely but that is how I felt about it ).  I found there was sufficient space to the right of the accelerator pedal, high up so it was tucked out of the way and would not interfere with the operation of the pedal.  The easiest way to fit it was to mark the position of the lower mounting hole on the bulkhead from the inside. Drill through the bulkhead, The upper hole is more tricky to reach but this is easily done by transferring the engine bay. From the inside the wheel arch the hole just drilled can be easily seen.  Using the inertia switch bracket as a template ( Turn it upside down so that it mirrors the fitting of the switch inside the car.) mark the position of the upper hole and drill the bulkhead.  From inside the car fit the inertia switch with the reset button at the top. I made an adapter to connect the wiring loom to the switch. I used blade connectors to connect to the loom and bullet and snap connectors to connector the inertia switch.  The intervening wires were covered with PVC tubing.




Fuel Injection

If you are not running a fuel injection system then the following is going to be Double Dutch  to you.  I took another look at the starter relay today.  I had a niggling feeling that I had made a mistake in wiring it up.  The loom at this point has 2 x thin White / Red leads set in to it. One I had correctly identified as the wire from the ignition switch the other I had interpreted (from the build manual ) as being the starter solenoid wire. As I said earlier  it did not look big enough to handle the solenoid current and I had used the wire from the XJ6 to make the connection from the relay to the starter solenoid.  Which left the thin red/white wire spare.  This wire ends up in a short loom close by together with a thick brown lead. The brown lead looks like the feed to a "free" brown lead that goes into the ECU wiring loom.  When I enquired of Nostalgia about these leads it was indicated that they were something to do with the Fuel injection system, but nothing more specific than that. Talking to Simon yesterday he more or less confirmed that the Brown leads should be connected together and the Red/ white lead should be connected to the flying lead from  the diode unit. but the question was from which pin of the starter relay.  A look at the lead from the diode unit it is coloured White  / Yellow,  the same as the lead in the ignition switch.  Examining the Wring diagram in the HM shows the wire coloured White / Yellow from the diode unit eventually winds up at the ignition switch and the lead that is connected to the starter relay W2.   I  did dome more research and trial fitting  of the wiring  I could connect  the ignition switch (white /red ) to terminal W2 and since the diode unit and the starter relay were close together the flying lead from the diode unit could be connected to a spare position on the W2 terminal. thus I did not need to use the spare White /Red lead at all.


Total hours this month 75= hrs


Total hours to date =  1845 hrs