1986 XJS dash insturment cluster wiring (LEDs)

I have taken the insturments out to put LEDs in there. First time doing anything like this. Got the back light green ones in and tested ok with 12v batt. One of the copper connectors is broken on one bulb socket. I could only get one of the warning lights to test and light up. Negative appears to be at the top of the warning LED bulbs.

I have fried a bit of the board when putting the 12v wires in the wrong place. Groud to groud. See the pic. How to fix this??? It looks like ground screw in the middle to the groud bar at the top. Could i just run a wire between the two screws and that would work?

Hello Simon and welcome to Jag-Lovers - lots of helpful people on here and lots of information - if you can locate both ends of where that ribbon path terminates, then get a piece of 30 gauge wire, such as one strand out of twisted speaker wire, and connect the wire to the two ends you found of the circuit path, as a temporary fix - just make sure that the replacement wire does not touch anything else - possibly secure it with tape - if you are good with soldering then you can acquire a ribbon strip to repair that section - hope this helps you - Tex.

Hi Terry, thanks. I have tried that see the pics. I put back in the car today. Car started fine. All on the small LEDs did not work, i turned a couple around and they bearly work as it flikers on and off. I think the LEDs are cheap and bad. The green back lights work. Oil P gauge was showing higher than before, now normal reading of 50 at stat then down to 20 - 30 after warm up. Temp gauge was higher above the N and would go higher when dash lights on. This was from the start so engine not hot. Ignition off and then lights on and the temp goins all the way up off the scale. Also the speedo does not work and no didtance registering on the trip conuter after short drive. I put new bolts and washers on the back, zinc plated and clened the contacts.

I will put back all the original bulbs as i know all the bulbs work. I think the wiring must be causing a short around the temp and speedo. Maybe i have done it wrong. Also my trip on the speedo will not manual reset.

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I have felt your pain as I installed LEDs in my ‘83 XJS a couple of years ago. First, don’t assume all bulbs are oriented with negatives in one orientation. Every socket polarity needs to be verified, bulb installed, and bench tested. Carefully clean and inspect all of the numerous circuit connection points including all the plug contacts, screw connections, bulb sockets, ground bar connections, etc. The final fix on mine involved a combination of jumpers (as on yours), addition of adhesive copper tape and solder in bad areas around the plug-in connectors, and addition of a separate ground wire w/connector from the ground bar to the car chassis. It took about 6 or 8 trial fittings of the instrument panel into the dash to get everything to work as it should. Different gauges and bulbs would drop in and out with each fitting. Gauges are extremely sensitive to voltage drops across connectors, and there is a rediculous number of connectors for each circuit in just the instrument cluster itself.

Now, is the modification worth the trouble? Absolutely!!

How do you dim the backlighting when the lights are on, or it’s dark?
I have cars where the backlighting in the complete cabin is permanently illuminated and dims when the lights are turned on.

LED’s won’t dim as they draw so little current the rheostat can’t reduce the current sufficiently.

When I did LEDs in the instrument cluster and warning lights, that was the problem that I ran into.

The speedo/tach/barrel instruments were far far too bright at night and I couldn’t dim them. Ended up pulling the LEDs back out of those and putting regular green incandescent bulbs back in. Left the LEDs in the warning lights/turn signals.

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Backlighting has been much less of a problem for me than not being able to read the instruments at night. The only frustration has been light washout of the odometer in the dark, a relatively minor inconvenience. But if your eyes are sensitive to bright lights, you may find a full LED replacement to be too intense.

No problem here :grimacing: … I have no glare tolerance at all, so I no longer drive at night as oncoming headlights blind me, I’ve actually had to pull off the road and stop a few times before I stopped driving at night. :face_with_spiral_eyes:

I have LEDs at all the lights at the center console and they dim uniformly with the incandescent bulbs.
If they don’t you can add a resistance, in series or in parallel, or both.

Thank you all for replies and tips, very mich appreciated. I took the cluster our again and put back in all the regular small bulbs, left in the back light LEDs. I then cleaned up the contact to the groud plate and copper strip and put the new ground wire i made between the copper strip and plate, around the screw. Not between rhe washer and screw. This worked and now the temp guage was behaving impeccably, even sitting just below the N all the way through a 2 hours drive on motorway and city. Was firat drive out in 5 month’s. So the groud wire looks to be working well.

Final problems

  1. speedo does not work and no signal to trip conuter 0 miles after driveing. Ignition off and turn lights on and all back LEDs light up. As i turn ignition on the back left (as i look a dash in car) goes out behind the speedo. Part of one side of the copper contact is broken and i have the piece.

  2. Now there is a bulb in the OXY SEN, it is constantly on, showing red. I think last owner removed this to pass EU chack. Do i newd to change the sensors in the exhausts?

I installed LEDs for the turn signal indicators and the high beam only and am satisfied with that… however sometimes when one of the indicators kicks off both indicators flash just for a second … retrofitting sometimes goes against itself…

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