Richter12x2

Neat problem, huh? The weirdness of some cars never fails to amuse me. Just as it sounds though, my reverse lights work just fine if my headlights are on, but don't work if my headlights are off. From a troubleshooting standpoint, I'm at a loss, because it sounds like the relays, connectors, and switches are all working, or it wouldn't work at all.

Any suggestions?

dprantl

Bad ground causing current to flow where it is not supposed to?

Dan
'91 928GT S/C 475hp/460lb.ft

Richter12x2

I followed the grounding diagram, polished and reconnected all the grounds 8 (garaged) months and <2,000 miles ago. Something weird is definitely going on, though.

Alan

Is it a manual or Auto (what year)? - makes a big difference in troubleshoting

Alan

Richter12x2

Sorry about that - it's an '85 US Auto

Alan

Have you removed the Central Electric panel for any reason? are al the grounds correctly (and tightly) connected above/behind the CE panel.

Auto's have reverse light relays for switching, manuals do not.

Alan

lawndart

Long shot, but I've seen it before, could the tail lights be installed in the reverse lights? do the tail lights work, or do they come on with reverse?

Richter12x2

All the other lights work normal, and the reverse lights that come on with headlights only come on when the car's actually in Reverse. I'll check the relay and the grounds for the CE panel, though. It hasn't been out, but it's still something to check.

sharknoob

With the ignition on headlights off is fuse 2 hot
By all lights do you mean the hazard lights work normal ?
Does relay XXll pull in with ignition on headlights off and in rev

LT Texan

I would have thought that this was normal.

If you don't need the headlights, why would you need the reverse lights?

I wouldn't have a clue where to find documentation of correct behaviour.

Alan

No its not correct behavior - the reverse lights serve the purpose of warning to others AND rearwards illumination (illumination almost as a secondary item - its not that great anyway).

Reverse lights should work whenever the ignition is on and the car is in reverse

Alan

Richter12x2

I wondered about that, too, actually. I had to observe some other sharks to know for sure.

underdog928

Question: Do your PRND32 lights also only work with your lights on?

If so, the problem is the small switch underneath the pod controlled by the ignition switch. That switch provides power to both the PRND32 lights AND the backup switch, which ALSO receives power from the lights. Weird wiring but that is why they are related.

Look at this thread: https://rennlist.com/forums/showthre...ferrerid=33607

Hopefully that will help.

Richter12x2

THERE we go! That's why I posted rather than dig around the car for four hours chasing wires that made no sense! Yes, you are exactly right, the gear selector lights in the console only come on with the headlights, so I'm betting you nailed it.

If you were closer, I'd buy you a beer! If I'm ever up in Maryland for a few days, I will!

WallyP

Bob,

It is always great when someone comes up with one of the oddities that the 928 electrical system has in plenitude. Thanks for adding to the group intelligence!