Warning light question

[Biggs_97]

I have a coworker that owns a 1985 928s and since I own a 944 and am always on the forum, he has asked me to help him with a problem. After his car sits for period of time, two weeks max, when he gets in to drive all of the warning lights on the dash come on and stay on. He has told me that it happened once after he purchased the car but after a couple miles all the lights went off. Now though, they stay on constantly. He has put a new battery in within the last few months and when he doesn't drive it it is on a trickle charger. Any help would be greatly appreciated.

[neil30076]

Usually caused by either a weak spring return in the electrical part of the ignition switch, or a bad switch. Tell him to try moving the key back slowly counter-clockwise and see if they go out.Either way, switch needs replacing, not the lock assembly.

[Alan in AZ]

I think you will find it means the alternator isn't generating.

On very early cars the lamp check was terminated by the starter, later cars terminate bulb check only when the alternator starts generating - this means the exciter line (61) from the pod (that controls the charge lamp on the voltmeter) goes to battery voltage. You can test this with a voltmeter on Central Electric Pin M13 (or L23)*. When running this should be at battery/system voltage - if not generating it will be a max of a few volts...

* for an '85 - other years vary

Could be a short to ground somewhere on 61, an OC won't do this - but most likely is a fault in the alternator's regulator.

Alan