Freakin' frackin' headlight issues.

[Piece-it pete]

Background: Autolamp/autodim system. Front parking lights were already dead, no power from the firewall. Everything else OK.

Then, smacked a rock at the end of someones' driveway. No headlights, lows or highs.

I finally managed to get headlights thusly: with the autolamp off, turning on the brights got all four lights on. So I unplugged the highs. I don't know if the autolamp being off matters, I'm afraid to try it differently and lose all lights again

I did check the pass fender ground and it is connected.

I figure I'll start with the headlight switch, I do have a spare. Any suggestions or tricks to changing it?

And any idea what else it may be? I'm guessing I got a power surge when I wapped the rock that blew something. I've got the electrical troubleshoot manual and it shows no fusible links etc, that there is a circuit breaker in the switch. But if that was blown I would think the headlights would be dead period.

Pete

[gadget73]

to repeat what I said elsewhere before I saw this, if its got autodim its probably the hi/lo beam relay. If its not autodim, my vote is on the MF switch. Power comes through the headlight switch no matter whether its on high or low, and since high beams work, the switch must be good.

[Piece-it pete]

I'll repeat my answer too, in case this thread gets searched out. I'll stop with comments in the other thread

This Saturday it's finally supposed to stop lake effecting on us, I'm going to boogie down (up really, if north is up) to pull a part, get some relays, a box for the headlight relay mod, and a MF-ing switch lol just in case. And a fender brace and ditch light assembly. I assume any box MF switch will be OK.

I will report back. Thanks gadget!

Pete

[sly]

any MF-switch should be fine up to 89 IIRC.

[gadget73]

umm, you want ideally 85-89. You can use an earlier one but those dont have flash to pass and they have the push-in horn stalk thing. The horn function wont work on a later car unless you wire it in, but I sort of miss flash to pass. I've got an 84 switch in my car. The older ones will fit and plug in though and have all the important functions work. I'd bet its the relay though, I don't think the MF switch carries much load in autodim cars. I think it basically just carries enough current to switch the relay rather than the whole load of the headlight circuit.

[sly]

oh right... I should know that... my Mark has that push in horn crap.

[Piece-it pete]

Thanks guys. Yeah my 84 Grand Marq had the horn on stalk, forgot about that, and I'd really miss flash to pass.

Pete

[Piece-it pete]

Anyone know where the flash to pass relay is? It's on the schematic but not the location drawing.

Pete

[Piece-it pete]

Not the relay - dang it!

On the TC the relay is just to the right of the headlamp switch. Pull the trim, there's a screw head showing, unscrew it, the relay will then finagle out between the dash and the steering column.

Assuming that is actually the flash to pass relay. Anyway, it was a relay, and I changed it

On my 85, the multifunction switch is held by phillips head screws. Get to the JY, the 88 GM with the stalk in beautiful shape is of course held with torx :grr:

Nice day for a drive anyway, rain to sleet to snow.

T20 size torx for the record. Also, a socket T20 won't work, I needed to use my cheapie screwdriver style on the top bolt as it is recessed a bit.

I should have it changed tonite, I'll continue with undates.

Pete