1978 280z w/no headlight power. HELP.

[aychummy]

Hey guys, I have a 1978 280z and the head lights went out on me. I have no high or low beams. I checked the fuses ( they are fine ). I checked the bulbs ( they are fine ). So my guess is it has to do with the wiring. I also heard that this was a common problem among Z's. But it has left me clueless. If anyone has any idea please let me know.

P.S

All the other lights work fine, back and front.

[FastWoman]

I think the common denominator in the wiring (between low and high beams) is the ground. I'd check that first.

You can download the factory service manual for free (!!) at...

www.xenons30.com

Welcome, BTW!

[beermanpete]

The headlight fuses are after the headligth switch. If there is voltage at the fuses when the headlight switch is on the switch is good. The dimmer switch selects the ground for the desired beam. If it is bad there will be voltage on all three terminals of the bulbs when the lights are supposed to be on. If the high beam indicator does not light the problem is in the dimmer switch or its ground connection (this assumes the indicator is working correctly otherwise).

[aychummy]

Thank you fellas, I'm going to check it out again today and i'll let you know if i find the problem.

[Zed Head]

Check the contact switch on top of the steering column also (or close, wherever the headlight switch stalk ends). The tiny circuit board can get loose and let the contacts lose contact. You can unbend the four crimped hold-downs, pull the board and clean the contacts. When you put it back together, crimp the hold-downs extra tight.

If you want to check it before taking it apart, just press down on it with your finger and see if the lights start working.

The dimmer switch that beerman mentioned should also be looked at. You can spray contact cleaner in to the switch area and work the lever to clean it up. Or you can attempt taking it apart.

I had the loose column switch go bad on a 78 parts car, and a dirty dimmer on a 76.

[SteveJ]

Search through the electrical section. I know that I've described the headlight circuit in great detail.

[aychummy]

Alright so i finally had time to work on the car today, and this is what happened. I got into my car and turned the lights on, BAM they worked out of nowhere. The high and low beams worked fine. But about two minutes later they Died and wont turn on. So maybe you guys could diagnose this from here? If the lights power on, wouldn't that mean that the cables are fine, except for a shortage somewhere? The fuses didn't blow when i checked them down in the corner of the passenger side. As for now, i'll check for a ground in the diagram. As a side note, the dimmer seems to work fine.

[beermanpete]

Alright so i finally had time to work on the car today, and this is what happened. I got into my car and turned the lights on, BAM they worked out of nowhere. The high and low beams worked fine. But about two minutes later they Died and wont turn on. So maybe you guys could diagnose this from here? If the lights power on, wouldn't that mean that the cables are fine, except for a shortage somewhere? The fuses didn't blow when i checked them down in the corner of the passenger side. As for now, i'll check for a ground in the diagram. As a side note, the dimmer seems to work fine.

On our car the headlight switch is worn or dirty. This makes the headlights intermittent. If I jiggle the switch a bit the lights will go on and off. Try exercising the switch. Also, take the steering column covers off and spray contact cleaner into the switch. Use lubricated cleaner or follow with spray lithium grease. That might help.

[FastWoman]

Yes, your WIRES are probably just fine. As we've been trying to say, it's a switch or connection (e.g. ground) that's at fault somewhere. I think Pete's suggestion of juicing the various switches (particularly the dimmer switch) with contact cleaner is a good one. I'd also trace the ground wire from the dimmer switch to the ground point, take that connection apart, clean it, and bolt/screw it back down. Putting a dab of dielectric grease in there before bolting/screwing it down is also a good idea. I'd bet money that your problem lies somewhere between the dimmer switch and the ground. I suppose it's also possible it could be a fusible link issue, but I think you'd notice other things not working too.

[Kuro]

One of the simplest things to check would also be the connections at the front of the car, there's a 3 prong connector on each side. I know it seems like that would not be the cause, but trust me, both of my headlights decided to stop working at the same time also, I had other lighting issues that I ended up resolving, but the headlights would not stay on. Those connectors were the cause because they were not making good contact. I cleaned up, put a little dielectric grease on them, reconnected them (make sure you push them together real well), after that the lights worked.

Just another place to look...

[aychummy]

Hey guys, the lights WORK! It's as everyone pretty much said. The ground connection between the dimmer and the car was just barely hanging on in my case. I cut the wires and connected everything back together, bingo! Thanks for all the feedback and tips fellas, i can finally drive at night again .