Problem with the electrical-system

[mcNesse]

Hi!

I´ve just started a job on a 505 GTDT 1986 and run into some problems.

When the ignition is OFF, the clock on the dashboard works, the buttons under the clock (seat heat, emergency lights etc.) works, the window-elevators works and the heat fan works. But when i turn the ignition ON, then nothing of the mentioned things work. But the instrument-panel works and the car starts if I turn the key so far.

I´ve tested with another ignition-lock with the same result. Also it seems that all the relays are working.

Have anybody had this problem before? Maybe a fix to the problem?

Thanks!

- André

[Bean]

Hi Andre,

Sounds like your grounds are messed up, and there is a grounding tree on the steering column that could be the issue. Circuits sound like they're either finding power via a wiring short in the harness, or the grounds are messed up and the circuit is finding it's ground through the switch somehow.

I'd start with the grounds, and I'd also inspect the wiring for any burned wires that could be making contact across multiple wires.

I've had harnesses in two cars (86 505 TD estate, 89 505 Turbo) have wires short circuit and burn into the harnesses under the dash. Only way to find them was to find the burned wires and trace them back through the harnesses all the way back to the source of the short, or until the wire stopped melting it's insulation. If the melting stops - go the other direction until you find the source.

In my diesel it was the fuel cut off solenoid wire that shorted on the throttle cable and it burned back to the ignition switch, on my 505 Turbo gas it was the rad fan power feed that shorted in the harness and burned back to the fuse box.

If you start under the dash and follow the harness from the ignition switch you should see damage fairly soon if it is a wiring short issue.

Good luck!

Rabin

[mcNesse]

Hi Rabin!

Thanks! I will check this out and let u know how it went

André