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I have a 1984 US 928. My battery will die overnight unless I take off the battery cable. After unhooking the front jump post and 14 pin connector, I checked for continuity to ground on the larger cable that comes from the alternator, but there is none. However, on the three smaller red wires the multimeter will beep if connected to ground. Also there are several pins on the 14 pin connector that have continuity to ground. They are pins 1 (blue), 2 (blue), 4 (blue and yellow), 7 (red and white), 9 (black), and 14 (big yellow wire). I've found some of the wires on the 1983 current flow diagram, but it's not getting me too far. Where should I go from here? I haven't tested the starter or alternator, but it cranks strong and charges fine when I drive. The car drained a freshly charged battery in under 24 hours so I know it isn't my battery. I'm missing a passenger side door switch, but haven't been able to trace any wires from it, and I haven't located it on the diagram yet.

Mrmerlin

close the doors and pull the relays out one at a time, see what ones click when they lose power this should give you a start also roll down the windows and check that the door side lights go out after the doors are closed look into the window slot to verify the lights go out.
I had a sticking blower motor relay and it would kill the battery in a day

RKD in OKC

When my 90GT was doing that the glove box latch was a little loose and not turning off the light in the glove box.

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Could a shorted horn wire cause the battery to drain? I remember once I had an incident with the horn honking anytime I turned the car a certain way, after yanking the center cover off and removing the wire it was still honking, so I pulled over and pulled the fuse. After looking for the wire today it appears it has snaked its way down the steering column out of view. Where can I find the end of this wire to either pull it out and run a horn button or push it back up the steering column?

Maleficio

Take some thick safety wire and make a hook on the end of it, then run it and try to snag it.

Tom928

On my 84, the red lights on the end of the doors were rusted and shorted together.

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When I unplug the three red wires coming from the jump post into the ce panel they are no longer shorted to ground from the jump post. Also, if I unplug "plug A" on the bottom row, and then reconnect the three red wires to the ce panel they aren't shorted from the jump post either. I think "plug A" is just the next main connection upstream from the three wires though which might explain that. Any other suggestions?

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Ok. It's pin 8 on plug A that has continuity to ground. I feel like I'm getting closer. I just hope I'm not tricking myself haha.

WallyP

The terminals on Plug A for an '83 are:
A1 - Flasher switch Terminal 30; ignition switch Terminal 30.
A2 - Light switch Terminal 30; ignition switch Terminal 30.
A3 - Ignition switch Terminal X.
A4 - Ignition switch Terminal 15.
A5 - Ignition switch Terminal 15.
A6 - Ignition switch Terminal 50 (starter).
A7 - Seat belt relay
A8 - Foot well and door lights.

One of the first things to check when the battery is being drained is the interior light circuit. Do your interior lights operate exactly as designed? Do the interior lights go on when the doors/hatch are opened and go off when it is closed? If not, I would strongly suggest that you start your investigation there.

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Any of the interior lights will come on when switched to the always on position. They door open only function didn't work when I got the car, but a week after I got it I replaced all the fuses and sanded all of the fuse holders for a good connection. Once I sat back down in the drivers seat to rest I shut and opened the door and the lights worked great, but within two minutes they had quit working again. My cigarette lighter was shorted also, but after bending the positive tab on the back it seemed to quit blowing fuse 5. Must have been rubbing the torque tube tunnel. I'll dig into the lighting circuit. Thanks. I curse the previous owner for neglecting the car. The transmission had absolutely NO fluid inside of it when I got it. I didn't discover this until after driving it for six months. These cars are tanks!

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The nut which holds the passenger side door switch was there, but the switch was missing out of the middle, but I did manage to get the brown wire out through the grommet to the inside of the car. With all other doors closed, it made no difference if I grounded the wire or had it just hanging there, the red door light stayed on. Am I correct in thinking if you ground the wire the car should think the door is shut?

*A slight correction to my previous post- The interior lights work in both positions, and will turn off in the middle position, but will not turn off with the doors shut, with or without the passenger door switch wire grounded.

Mrmerlin

no the correct way for the lights to work is when the pin switch is pushed ( wire connection broken) then the lights should go out when the wire is connected to ground then the lights should come on. Since this might be a lighting issue, I would suggest to remove all of the lights inside the car and inspect them for thew correct wiring connections.
the brown wire is chassis ground and connects to the light frame
the brown/ white stripe is switched ground to the pin switches , this will also test out to the light frame when the switch is moved so you know where the switched wire is connected
the hot wire is red and is a different color for the top of the hatch and the rear of the hatch use a test light to confirm the hot wire .
Use a test light to figure out where the power wire is connected. with the bulb removed it shouldnt have any continuity to the light frame
i dont have any pictures but if you connect them wrong all kinds of lighting issues will result.
Also get some heat shrink and recover all of the leads to the interior lights if one of the power wires breakes off the light housing , then it can melt the whole harness.
Any light fixture thats melted should be replaced, dont try to fix it as the plastic is brittle and could be a snap away from a harness meltdown

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On page 97-201 of the wsm, (84 wiring diagram) the door contact switches seem to imply that when the switch is in the extended position that the ground is broken. That's what I was thinking anyway.

Mrmerlin

nope, its the other way around when its pressed the ground contact is broken

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I have pulled plug F which the brown/white wires from the door contact switches run to on pin 5. The short is not in the brown/white wires leading to the plug, but pin 5 on the ce panel for plug F has continuity to ground. Where should I look next? I can't seem to get any further with the wsm.