Cheerful into the 4th day of owning my 'new' 1987 Series 3 and feeling confident I'd really found 'that gem' of one. First night drive home all was lit on the dash and center stick. I was smiling thinking the prior owner had conqured Lucas. And then on the second night of driving home, WAM!, I'm in total cockpit darkness. Headlights and tail lights all look to be okay but the only thing on is the computer and the high beam indicator. I step on the brake and the tail brake lights work but I get that little bulb bad indicator on the dash.

Before I spend the usual endless hours chasing my tail around on this, anyone have a few hints as to where to start?

 

To clarify "total cockpit darkness", the instrument lights, courtesy lights, and warning lights (except high beam and bulb failure) are inoperative?

That's an odd combination of circuits to fail all at once! Off hand I don't think they have anything in common.

Anyhow, start with fuses, of course. Besides checking if any are blown make sure the end caps are clean and shiny, and the fuse clips, too.

Next check the plug-in connector for the gauges and warning lights. Two separate connectors, as I recall.

There's a ground wire (maybe two) that should be attached to the metal dashboard backing panel. Look in the area of the tach or speedo (maybe both), towards the bottom.

If the courtesy lamps are inop, that's a different kettle of fish.

More later. I'm still on my first cup of coffee :-)

Cheers
DD

I'll need more coffee

 

Thanks Doug for the lead. Just checked and the interior cabin lights are working, just the gauge lights and the shifter lights are out. I'll try bypassing the rheostat and see if that works but would that affect the shifter light also?

 

Yes, the gear shift light is on the rheostat as well

Cheers
DD

 

Well, not long after I got my Jaguar, in 2001, I was in the local old time gas station, now gone, filling up the novelty of twin tanks with novel locking caps!! A lady was tanking up her car. She remarked that she had to dispose of her beloved Jaguar and replace it with a "simpler" car. It's electric issues had eaten deeply into her pocket book!! I thought, "Oh me what have I done this time?".

Well or a diyer, not all that bad. I've concluded that the wire guage at a minimum and the connectors leave a lot to be desired. Further, that high under the bonnet temperatures cook insulation. My experience with 6v systems carried over. All joinery must be clean and tight. Grounds must be nigh on to perfect. Jaguar electric mantra, clean, tighten and lubricate.

For the inline glass fuses, a pox on whomever decided to hide them about the car!!
They might look good but be open inside. Test to verify or just swap them out. The underside of a fuse panel can be corroded and defy normal circuit testing. Just scrub hem clean and faults will vanish. or at times, just a finger roll of them in situ will restore the circuit???

he courtesy lamp switches in the door posts are marvel of miniaturization. But, they wear in a way that I've not been able to fix? Lateral slop in the moving post!!

There is a braided ground on the right under side of the car connecting the frame to the transmission. Grunginess here can do weird things like welding throttle cables!!

And, I earned a long time ago that a sheathed battery cable might look Ok externally, but be badly corroded internally!!

A VOM and test lamp is a must for these cars.

I enjoy mine very much. Although it was a tad hot and the AC in my car is not yet on line, I chose it to go to the local animal rescue shelter, Not a dog and cat pound. Coco Hutchins, a 27# slightly over weight mutt rode home with me. He didn't know what to make of it?? Car ridding apparently not a part of his prior six (estimated) years!!
That will change!!!

He seems to like it here and wants to be right where I am. Curled up at my feet now, as I type.

Enjoy your Jaguar, travails an all. Lots of help here to overcome any of them.

Carl

 

I thought I'd solve my no dash lights problem with a simple by-pass the rheostat. That seems to be the solution I've read everywhere. Now, how the heck to I get to the wires behind the rheostat? I've read I cold take the computer face out and with small hands unplug the wires off the back of the rheostat. Trouble is, how the heck does the computer face come off?????

 

Just get your fingernails under the edges of the trip computer and wiggle it out. It's held in only by friction.

If you can't reach the rheostat wires through the opening you'll have to remove the wood panle. Post back in that case.

Cheers
DD

 

Well, I dug out the trip computer which turned out to be pretty easy with Doug's instructions. HOWEVER, after disconnecting and bypassing the rheostat by joining the 2 ends of the wire, I STILL DON'T HAVE ANY DASHBOARD LIGHTS. Any further ideas? Thanks....

 

Do you have a test light or test meter?

Check that the red/blue wire to the rheostat has 12volts with the headlight switch "on".

If it does, and it's joined to the red/white wire at the rheostat, then your panel lights should work....unless you've lost your ground, as described earlier.

If you don't have 12v at the red/blue wire then you have an upstream problem. Post back.

Cheers
DD

 

Well Doug, after my 2 cups of coffee, I went with my trusty volt-ohm meter and started digging around. It turned out to be the fuse #8 under the drivers side panel. And although that's where I should have started off looking (being an ex-USCG Avionics Tech) by bypassing the rheostat anyway, I should have dash lights which are now bright enough to see the instruments at night, not a vague ghost of an image.

Appreciate your help and everyone's input.

 

Look at post#2, third line

Heh heh, just rubbin' it in a little! I really no room to talk. I have tons of experience overlooking simple fixes


Cheers
DD

 

I know, never overlook the simple first. But after reading so many threads I was sooooooo sure it was the rheostat. Duhhh! But, as I say, I wanted enough light to see the gauges by anyway and the only way for that was to bypass that rheostat. I'll have to see them tonight if that's true or not.

 

Last night I got my first look and use of the dash lights without the rheostat in the system as I bypassed it. I can now see my gauges!! Not overly bright, matter of just right, but I can now see the things without having to work at it. I'd recommend this easy mod to everyone!

 

Yup! Good work!

I did the same with my Series III and my XJS.

Eventually Jaguar got over its love affair with dim panel lighting. On my '95 have have to actually turn *down* the intensity of the instrument lighting....it dazzles my eyes!

Cheers
DD