shaaark89

so i'm a bit puzzled by this one.

ignition off, marker lights come on main headlights don't go up or turn on(normal)
ignition on, main headlights come on before they raise up (not normal) and do not turn back off if switched to marker lights only (the lights stay in the up position which is normal)
turn ignition off at this point (switch in marker only position, headlights up and on)
and everything stays on. turn off switch and everything stays on. i have to turn ignition back on to get lights to turn off.
i have switched the light relay with a normal functioning one (from the 91 gt) and checked all the light fuses. same behavior all fuses are good.

thoughts?

Landseer

Did you try switching the switches?

Jadz928

Check the lamp control module on the pax footwell tray. Pull it open and check PCB for corrosion at solder joints and trace continuity.
Or swap w/ known good unit.

Not sure if headlamp power goes thru there but I'm sure most lamp pwr does.

Also check ground points at front of car.

Erik N

Failing ignition switch?

dr bob

Tom--

Clean ground point MP-I, front apron left side near the ignition amps.

There's a possibility that your X-bus relay is sticking. Try replacing this with a known-good relay. It's a standard 53B relay, interchangeable with the horn relay among others. Relay X sits in position IV in the CE panel, while the horn relay is in position XII. There would be other symptoms related to accessories still running but you might not notice them as you focus on the headlights issue. The X-bus relay interrupts current to the headlights when key is not in 'run' position.



If that doesn't do it:

The X-bus relay is energized from the 15 bus from the ignition switch, so the next diagnosis would be looking for voltage from ignition switch circuit 15 showing up at terminal 86 on the X-bus relay with key not in 'run' position. There would be a lot of other symptoms if the 15 circuit is live with key off though. Test in the X-bus relay socket, relay removed. Pin ID's are on the bottom of the relay case. Use a test light or low-impednce meter if you have one.


If that doesn't solve it, get a test light or voltmeter and:

With the settings at the point where the key is off and the headlights are still up and turned on, check for voltage at C11 and/or C14 on the CE panel connections, report back your findings.

shaaark89

thanks for the input.
dr bob, thanks for the "recipe". always nice to have a sequence to follow.
interesting that i have had a couple of hot start issues recently as well. cranks but no start. let it sit a while and it's fine. i wonder whether the two issues could be related?

Alan

headlights/fog lights/aux driving lights are not monitored - only rear & rear/side markers and stop/brake lights are monitored.

If what you say is exactly true (e.g. marker & headlights stay on with the light switch in off mode) - it seems there must be a problem with the light switch.

Some of the behavior - lights coming on when down - sound like a problem also with the motor feedback switches...

I'd first try swapping in a known good main light switch.

Alan

shaaark89

ok so i tried dr bobs suggestions:
cleaned ground so it's shiney, no difference
switched x relay, no difference
power at terminal 86 of x relay is 0.0 volts with ignition off, 17 volts with ignition on
key off headlights up and on, voltage at c11 and c14 is 13 volts

interestingly, while i had the x relay out of the socket, the headlights would still go on with the ignition on and behave the same way though the fogs would not go on.
i'm lost......

Hilton

Tom, this rings a bell - most usually a topic raised on UK cars (I have a couple of ex-UK 928's).

This thread here:

https://rennlist.com/forums/928-foru...blem-help.html

And more about the connector T5 in this one by Wally:

https://rennlist.com/forums/280980-post10.html

AO

Get rid of the car, and buy your old GT back from Afshin. Fixed!