The power windows, AC, turn signals, radio, brake lights all stopped working at the same time. I have checked all of the fuses. Checked the relays. Somebody told me to replace the ignition harness. After buying one off of JagBits. No go. This is my Dad’s baby and he was just diagnosed with cancer. Would like to fix this so he can enjoy it again.

 

lf it where me the first thing i would have done is have the battery checked or replaced (checked as in properly)

Then fuses and relays. No disrespect ment, but have you checked all..............................as they are all over the place, in the boot, drivers and passengers footwell and all over the engine compartment.

Then i would check the earths, not sure how many there are on the later models, there are about 16 (counting one 'end' as one') IIRC on the earlier ones.

If you still have no joy someone will be along shortly with some more info on how to dig deeper.

......................................also, did you get caught out in the rain? lf so hows your windscreen rubbers?

 

Douglas,

As AOI has said, this looks to me far more like a power supply problem than the integrity of the harness.

You haven't mentioned if other circuits are also out. Does the car start / turn over etc? With all the other areas that are ignition-controlled, I wouldn't start by thinking there was an issue with the ignition harness.

I would start by:

- checking the integrity of the positive and earth connections on the battery (I guess they are ok as you must have removed them when changing the ignition harness)
- check the voltage and earth integrity of the bulkhead +ve and -ve posts. These are known issues. If you have less than perfect voltage and earth checks here, start looking at the integrity of the posts and the supply cable from the battery to the bulkhead.
- go through the wiring diagram and look for a common earth connection that links the failed circuits

Good luck

Paul

 

The car starts and runs just fine. Just those electrical systems failed. I will check the battery cables etc.

 

Have you checked the auxiliary ignition load relay? I had a similar problem with certain items (windows, a/c, radio, and turn signals, from memory) going out in my 92 XJS and it turned out to be this relay. It's located under the glove box after you remove the underscuttle panel. It's next to the identical seat heater relay. My seat heaters were working so I swapped those relays as a test and everything except the radio started working again. So I ordered a replacement relay and didn't have any further problems. For the radio, I did have to replace the fuse under the ski slope as I recall.

 

Is there anywhere on here where I can find out where to find the correct relay? I don’t have access to much.

 

Once you diagnose the cause, you can contact one of the forum sponsors, such as SNG Barratt for any necessary parts.

 

That worked. I switched the relays and it fixed everything but the radio. Now to find the replacements for them.

again. Thank you to everyone who helped.

 

Do you mean where to find it in the car or where to buy a replacement? Once I pulled the bad relay out I just googled the number on it and ordered a replacement on Amazon. I recall it was a Bosch 5 pin and readily available.

If you mean where it is in the car, here is a link to the 1992 XJS electrical guide: http://www.jagrepair.com/images/Elec...electrical.pdf

If the link works, Page 7 shows the location in the car of the "right component panel" and page 8 shows the detail of that panel and where the aux load relay is. I may have some photos in my old photobucket files I can look for if you can't find it.

 

Nice. An easy fix.

 

Ok now the radio only has power when the ignition is off. Even if the key is removed.

 

Sounds like relays have been mixed around or incorrectly replaced.

l always find that when doing anything like this its best to do one at a time. ln this regard ; disconnect battery, change relay, connect battery, start car an check ALL elec features................................and repeat, one relay one test sequence, no shortcuts that way you can pinpoint issues rather than going over everything you have done.