96 VDP started smoking from the trunk while driving. Shut her down and burning ceased. So now cars dead, battery might be dead, but when jumped with another battery I get power back to some of the car's systems (windows seats, etc) but won't crank starter. Harness is a burned mess. What could have caused this and what to do to repair?

 

Hi rfxj6,

I'm glad you noticed the smoke when you did, given the proximity to the fuel tank!

Off the top of my head, I'd think that the likely cause was either excessive current draw in a circuit protected by a high-amperage fuse like one of the 250 amp megafuses, or a short causing a current draw that was unprotected by a fuse. Do you have any aftermarket sound equipment installed, or any other modifications involving electrical circuits?

Repairing the harness may be possible, but it will probably be far more cost effective to purchase a good salvaged harness from a similar car. Those ground points will obviously need to be thoroughly cleaned, and you'll want to check everything carefully to identify and correct the source of the problem before you power up again.

For now, I would check to be sure your key works in the driver's door lock and trunk/boot lock, maybe even lubricate the locks with some powdered graphite, then disconnect both the positive and negative battery cables for safety.

Please keep us informed.

Cheers,

Don

 

Very sorry to see this! But it is another "could have been worse" scenario. My thoughts are that the battery puts out hydrogen gas, and is supposed to be vented via a tube to the outside floor. If the vent was missing or blocked, I suppose a fire could happen. I've seen warnings to that effect but don't know how "possible" it is in reality. I wonder if a switching relay could spark it?

Should be repairable with a new harness. At least you have a new XJ12 to enjoy while the VDP is parked up!

 

Thanks for the replies. No electrical accessories have been installed on the car. Battery was not vented as originals are with tube through floor. New batteries don't have the vent to attach the hose to. The burn appears to have started in the center of the harness and not at a relay, and no explosion was noted. Hoping an X308 harness is compatible as that's all I could find in short order. It'll be hard to find a chaffed wire in the harness, if that was the cause, because the wiring insulation is melted into a mass blob, but being in the middle of the harness run that might be the logical explanation. Will update as I make progress.

Yes Richard, the new XJ12 is an amazing pleasure. Almost de-golded at this point.

 

Well,

Within the past 3 years I've replaced the battery in our '04, and both the AutoZone Duralast Gold and Exide NASCAR Extreme Silver Shield batteries have vent holes.

I just did some work on a friend's Porsche 911 on which he had just had a new battery installed and it also had the vent holes, though the vendor that installed the battery had failed to hook up the vent hose.

All that to say that a correct battery for your car should have a vent hole at each end and you just need to remove a plastic plug or use a punch to pop in a molded plug in the end of the battery to which your vent hose attaches.

Cheers,

Don

 

Well,

You're correct. I learned something new about installing a battery in the boot. There has not been a vent hose in this VDP and I have not changed battery since I've owned it. This could have contributed to magnitude of problem but it really looks like a short. At the origin of the burned section of the harness, several grounds tie into the bundle.

Not sure if this a clue to why this happened or as a result but I removed the battery and it measures 1 volt and my battery charger dislikes it. It makes buzzing sound when connected to battery and the charge light doesn't turn on.

I'm having my doubts that the harness from the X308 will be compatible even know the ebay listing stated. Openly looking for a harness.

 

I'll be glad to help you get any harness that you need.
I have a few X300s being parted on site.. (I'm in NC)
If you want to email me, it's david@everydayxj.com

My wife and I have a 96 VDP too... Great car....

Cheers,
David
shop.EverydayXJ.com

 

@rfxj6 ...

Your best solution is to contact David Boger who posted just
above. You will find him a pleasure to deal with.

 

I totally agree. He provides a great service and is very responsive.

 

David, thanks for the quick help and the wiring harness. Great advice from the forum as I now have a great resource for parts. The replacement harness did the trick. Upon closer inspection I speculate a hole in the muffler immediately under the harness in the trunk allowed heat to soften the wiring, and in-turn, a harness hold-down post caused a short that turned into a melt-down. This actually happened during hot day last summer and the car has been sitting ever since.