Prize 850 went dead

[JimBee]

After a year parked on a gravel pad, the 96 GLT wagon started right up. I took it for a short drive around the neighborhood. Stalled a couple of times while idling, but restarted and ran okay—until I got back to my place and almost back into a safe parking space. Unfortunately, it died, this time it's really dead. Nothing showing on the digital display. I suspect the ground cable. Once, when I wiggled it I heard a motor whirring and the digital display did light up. I tried turning it over and it all electrics went off again. This time no amount of jiggling has restored the volts.

The negative cable on this GLT has one major lead that goes into a loom, looks like there might actually be several smaller individual cables in that loom. Unfortunately, that loom goes into a metal enclosure along the side panel, I can't see where it exits and connects.

There are also 2 separate cables not in the loom, one goes to bolted ground behind the left headlight. That's the first thing I'll clean up tomorrow. I'll need to pull the battery and air box to see where the other one goes, maybe to another engine ground.

Has anybody replaced one of these or have a wiring diagram?

[matthew1]

What's the battery voltage?

[JimBee]

battery voltage is 12.9

[JimBee]

I also tried jumping it from a running 850, jumper cables clamped to the dead 850 cable connectors, nothing lit up.

And I tried using a jumper cable from the negative battery post to a ground on the engine that was probably not the best ground. That actually lit things up for a few seconds with all kinds of scrambled digits on the dash display and a bright red led. Then that all went out and another attempt didn't produce anything.

Next test: continuity. With cable disconnected from battery, one probe on cable clamp, other on the engine. Should read 0.

When I installed the battery just before this happened, the negative cable clamp was kind of jammed beside the battery and I pulled on the clamp to work it free. If it was close to failing that might have further weakened it to a point closer to failure. Then just a little vibration from driving and total failure.

I'm assuming the negative battery cable has failed. But if it is a battery cable problem, it could be the positive one. If it isn't a battery cable problem I have no clue where to start testing.

[scot850]

I believe the 850's have a B+ cable to the positive side of the battery. On the later P80's with the kidney shaped main fuse box in front of the brake booster, this wire terminates at a bolt inside it. It can melt and fail causing the car in worst case to go on fire due to shorting.

I don't know from memory where it goes to from the 850 from the +ve side of the battery (it is the smaller wire).

Check all the grounds in the engine bay are present and correct and they have clean ground points.

Lastly, the electrical portion of the ignition switch might have become corroded inside after sitting.

Neil.

[foggydogg]

As I recall from my early 850 days there is a four pin power relay on the drivers side fan shroud. I had an issue with hidden corrosion on the wire connectors inside the moldex plug.
That bundle of red wires in the lug connector that disappears behind the airbox to power the fuse box is notorious for getting crud of ages internally.

[JimBee]

Fortunately I cleaned up the grounds and it seems okay.

Well, except the heater fan is on all the time and not responding to slider changes. I need to clear some codes but to do that I'll need to make up the LED gadget that Ben850 showed us. Next project.

[erikv11]

If you are unsure about the ground from the battery, run a fresh one from the cable to the body. Will tell you if the existing battery ground is the issue, or to look somewhere else.

Glad you got it running!

[JimBee]

I definitely like the easy fixes!