Weird starting problem

[e30newbie]

Hi guys,

I am having a strange starting problem on a 88 325i auto. Sometimes the car will not start when the air con button is on but sometimes it will not start even with it on or off.

When the non start problem occurs, it will not crank at all and I need to start it using the diagnostic socket method.

It is very annoying.

[Brianmoooore]

Can't see the connection with the aircon, as this is switched off automatically when starting, anyway, but your problem is most likely to be something to do with the starter inhibitor circuit for the auto selector lever. It's only a switch attached to the lever frame, a bit of wire, and a relay behind the glovebox, so it shouldn't take long to check out.

[e30newbie]

I don't get why the problem only occurs occasionally. How do I disable the starter inhibitor circuit just to check if it is the problem.

Thanks

[Brianmoooore]

Above the glovebox area there are two black/yellow wires hanging from the main loom with single pole plug and sockets connected to them. If you disconnect the wires that are not part of the main loom (the ones that go to the inhibit relay), you will find that the two connectors hanging down from the loom will plug together.
This is how manual gearbox cars left the factory.

[e30newbie]

Ok I have disable the inhibitor circuit to check if the non starting problem will occur again. I guess its just a coincidence sometimes the car will start after turning the air con button off. If it is related to the air con then it should start everytime the air con is off.

Thanks Brian. I will update if problem not solved.