Club 80-90 Forums

This is nothing to do with my van, but I'm having a few problems with my other toy car.
Can anyone tell me how the battery charge light output on the alternator should work.
Am I right in thinking that it is earthed when the alternator is not spinning/charging, then switches to open circuit when spinning/charging or should it go live when charging??
Help please!!

Mike.

Depends on what car some work through the engine ECU.

No mate this has nothing to do with the ECU.
Its a basic old Bosch alternator which came off a Cavalier GSI, but its now in a kit car.
Its got two connections one for power and one for the charge light.
It switches from earth to live when running which is causing a back feed through the dash PCB which is keeping the engine running when the ignition is switched off. I expected it to switch from earth to open circuit but must be wrong.

In that case it's working correctly. How have you wired the battery warning lamp.

The light is part of the dash binacle. It's +ve fed via the PCB from the switched ignition feed and earths out at the alternator. It switches on and off as it should, only it caused other problems. Just need a rethink with the supply or put a switch relay in it. For some reason I got it in my head that the alternator would switch from earth to open circuit not to a live feed.
Cheers.

Yes that's the way it should be wired.