Nearly all electric items in the front end of my 2004 XJ8 dies a few days ago. No headlights, brights, fog lights, wipers, gas door release, turn signals, emergency flashers, keyfob door locks, and probably a few more that I haven't discovered. It all seems to have happened after I turned on my emergency flashers. Rear items like my left and right turn lights still function although I have that "fast signal sound" when in use. It's as if anything that is controlled from the driver's dash is blown. The fuses have all been checked and are fine. ANy help would be greatly appreciated!

 

Can you DIY any of the repairs?
If not your only option is take it to a dealer and see what they say.
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Only to a degree but I have an excellent mechanic if it goes beyond me.

 

Couple thoughts to start with:

1. anytime there is an electrical issue, check the battery condition.
2. check the engine ground points, these break off with age and heat causing all sorts of problems. They are little aluminum posts with wire connectors and nuts on them. In my XJR, not less than 3 engine bay ground points had broken off. The ones that tend to get are behind the headlights (easy to inspect). A classic "headlight ground point broke off" symptom is if you start the car (does it start?) do the windshield wipers just have a mind of their own and start moving without command. If it does that, immediately check the passenger (US) side ground points behind the headlight.
3. get the electrical manual (the '04 guide is online) and look at the path of the systems that have failed. You are describing a common failure, and so you want to inspect the connections or systems that are shared. For example, shared control modules, shared power supplies and ground points would be where I would start.
4. also pulling error codes can help, though here you know which systems are impacted by their non-operability.

 

Thank you! It does start and run fine. I'll look into these.

 

+1 to scooterforever's comments regarding downloading a schematic for your year of car.

Looking at your list of issues and trying to find a possible common denominator........
From the list of things not working, check F42 in the passenger fuse box to see if it has failed.
If it is intact, check to see it has supply to it when ignition turned on. If no supply then perhaps relay R1 (system relay inbuilt in passenger fuse box) has developed a problem.
R1 is not a user replaceable relay, can be replaced if suitable replacement is found and you dismantle fuse box to get at it, otherwise a good second hand fuse box might be better option.

If fuse OK and supply to fuse is there, then perhaps move onto checking grounds.
Ground 9 - cabin / LH upper A pillar (grounds your front electronics module etc)
Ground 31 - behind passenger air bag. (grounds the instrument panel and thus some control switches like headlights etc.)

Good luck with your initial hunt.....let us know how you are getting on.

 

Thanks for the info!

 

Yes good suggestion about the ground posts too!
I have barely touched these before and they just came off in my hand. So they are VERY fragile and can't take much if any force. I usually shear the stud off while trying to remove the nut. Be prepared to replace them with SS threaded bolts.
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For what it worth,
When time comes I will use zinc plated or galvanized iron bolts to be used as replacement studs; you see, stainless has high content of chromium and nickel, those two metals are far away from aluminum on galvanic table. You want to put together metals that are close to each other to prevent galvanic corrosion. Also to consider: metal that dissolves has lower order in table out of two. in other words: zinc will turn into dust not aluminum nor steel; in case of aluminum in contact with chromium, aluminum will disintegrate, while stainless will stay undamaged.

 

So, here is the result of my issue. All is fixed! Here is how my mechanic described it. The computer systems that control all the front-end electrical systems I had issues with shut down due to my alternator. The alternator could not keep up with the draw when all my lights, door open, climate control, radio, and then the final straw when I put my emergency flasher on. They just all shut down. He tested the alternator, found it to be an issue, and then replaced it with a remanufactured one. Issue solved with only two hours diagnostic labor charge (plus the charge for the alternator and labor to install). I got lucky with a good mechanic!