Headlight gremlins Options

[lierofox]

Wow, I didn’t know this... and it just gave me a headache trying to understand it.

So my best bet if I want to run fogs with the LED headlines is to completely separate the two circuits and run the fog switch directly to the fog relay?

You just have to pull the fog relay's ground wire off the high beam terminal, and move it over to a dedicated ground lug, then it'll always be grounded and the high beams won't cancel it.

Edit: Here's a little interactive/animated diagram I made demonstrating the circuit, you can click on the switch to turn it on and off, the wire colors show where the voltage is (green is 12v, gray is ground) and the yellow dots show the current flow.

http://tinyurl.com/tj74k43

[AZBanks]

Hijacking the thread since my issue is light related.

My light were working perfectly until about 4 nights ago.
The drivers side headlight does not go up when I turn on the lights. The light bulb is on but I have to turn the knob on the back of the motor to manually raise the light up into position. I will check the relay. Is there any other typical cause of this kind of issue I should check?

[john77]

Hijacking the thread since my issue is light related.

My light were working perfectly until about 4 nights ago.
The drivers side headlight does not go up when I turn on the lights. The light bulb is on but I have to turn the knob on the back of the motor to manually raise the light up into position. I will check the relay. Is there any other typical cause of this kind of issue I should check?

Sounds like the relay if the light's coming on. I went through exactly the same thing before I got around to putting in a new relay... and then these new gremlins appeared.

Just unscrew the plastic covers on the side of the motors, swap the relays over and turn your lights on - if the opposite motor to the one not opening now doesn't work, you'll know within about 5 minutes if it's the relay or something else.

[john77]

Wow, I didn’t know this... and it just gave me a headache trying to understand it.

So my best bet if I want to run fogs with the LED headlines is to completely separate the two circuits and run the fog switch directly to the fog relay?

You just have to pull the fog relay's ground wire off the high beam terminal, and move it over to a dedicated ground lug, then it'll always be grounded and the high beams won't cancel it.

Edit: Here's a little interactive/animated diagram I made demonstrating the circuit, you can click on the switch to turn it on and off, the wire colors show where the voltage is (green is 12v, gray is ground) and the yellow dots show the current flow.

http://tinyurl.com/tj74k43

That makes sense.

Moving the fog relay ground wire, the power to the fogs is still dependent on the headlights being switched on?

If I wanted to use them as independent driving lights I'll need to find a new power source to trigger the fog relay directly from the fog light switch, right?

[lierofox]

That makes sense.

Moving the fog relay ground wire, the power to the fogs is still dependent on the headlights being switched on?

If I wanted to use them as independent driving lights I'll need to find a new power source to trigger the fog relay directly from the fog light switch, right?

Yep! I forget which one but I think I pull power for my switch from either Fuse 8 or Fuse 9 on the under dash panel, so it'll still turn off with the key.

[Mikey914]

Hijacking the thread since my issue is light related.

My light were working perfectly until about 4 nights ago.
The drivers side headlight does not go up when I turn on the lights. The light bulb is on but I have to turn the knob on the back of the motor to manually raise the light up into position. I will check the relay. Is there any other typical cause of this kind of issue I should check?

I'd bet relay try to wiggle it around may just be a bad contact in the socket. But typically that would be a relay.







Anyone want to put me down for $5 on the switch for this thread (IMG:style_emoticons/default/popcorn[1].gif)

[john77]

I took the car out last night. Still no conclusive answer.

Warming up on my driveway, lights on, they work fine. 10 minutes sitting there, not a glitch.

I drove 20 feet down the street and they cut out. I tried waggling the switch, nothing.

I turn them off and back on and the lights either come straight back on (and then die) or they flip up, nothing for about 10 seconds, then they come back on, then they die.

Is waggling the switch supposed to have some effect if it’s the switch?

[lierofox]

I took the car out last night. Still no conclusive answer.

Warming up on my driveway, lights on, they work fine. 10 minutes sitting there, not a glitch.

I drove 20 feet down the street and they cut out. I tried waggling the switch, nothing.

I turn them off and back on and the lights either come straight back on (and then die) or they flip up, nothing for about 10 seconds, then they come back on, then they die.

Is waggling the switch supposed to have some effect if it’s the switch?

Looking over the wiring diagram there's a few possible candidates for a single-point-of-failure for the headlights.

From the ignition switch: Terminal X feeds power to a separate wire that leads over to...
The headlight switch: When pulled to position 2, power is supplied from input terminal 15 to output terminal 56. From there it heads over to...
The Dimmer Relay: Power comes in on terminal 56, and outputs to either the low beam terminal (56a) or the high beam terminal (F) and both lead over to...
The fuse panel: The low beam wire feeds to fuse terminal 4, which is always jumpered to fuse terminal 3, the high beam wire feeds to fuse terminal 2, which is always jumpered to fuse terminal 1.

At this point all 4 functions have split off to separate wires (low left, low right, high left, high right.)

If your low beams die, but you hit your dimmer lever and get high beams, I would inspect the wire between Fuse 4 and the dimmer relay. If those look good and solid I would condemn the dimmer relay.

If your low beams die, and your dimmer lever doesn't give you high beams, I would inspect between the dimmer relay terminal 56 and the headlight switch terminal 56 (if equipped, this terminal also supplies power to your fog light switch, terminal 15.)

Before condemning the headlight switch though, also inspect the power going to input terminal 15 on the headlight switch. If power is intermittent there, that means your ignition switch is suspect, try wiggling your key in the ignition and twisting it slightly, see if any sort of motion will cause your headlights to drop out without also killing the engine.

If your ignition switch seems fine, and no amount of wiggling it seems to set things right, you can try servicing the headlight switch. One of the failure points of the headlight switch is that the sliding contacts get worn/pitted, you can try disassembling it and inspecting the contacts and the springs that hold the contacts down. If excessively worn, I believe that 2 of the contacts are actually identical, and you can swap them around and reassemble the switch. (Not sure if this is the case for a '73 switch, it was true in my '75.)

From personal experience on my own 914, I've had problems with all 3! Replaced the ignition switch, serviced the headlight switch, and replaced the dimmer relay.

[AZBanks]

I went out to check the relays. Before I touched anything I pulled the switch to turn on the headlights and got the same behavior, the passenger highlight popped up and both bulbs turned on.
I pushed in the switch to turn off the headlights and the passenger light went down half way and stopped and both bulbs turned off.

I swapped the relays and pulled the switch. Both bulbs turned on but the drivers side stayed down and the passenger side stayed half down.

It looks like the relays are not the problem. Now I have to find out what is the real problem.

[Spoke]

I took the car out last night. Still no conclusive answer.

Warming up on my driveway, lights on, they work fine. 10 minutes sitting there, not a glitch.

I drove 20 feet down the street and they cut out. I tried waggling the switch, nothing.

I turn them off and back on and the lights either come straight back on (and then die) or they flip up, nothing for about 10 seconds, then they come back on, then they die.

Is waggling the switch supposed to have some effect if it’s the switch?

Wiggling the switch may not cause the issue to happen. Likely it's vibration introduced with the movement of the vehicle. Pounding on the dash may get the issue to occur but not guaranteed.

If it is the switch then you have to bypass the switch to test or just replace the switch. I'm not a fan of just replacing something w/o testing first. It could even be the connections to the switch or to the hi/lo beam relay.

Whatever you do to test or replace the switch, remove the negative battery terminal before touching any electrical components. There is no fuse between the headlight switch and the battery. Accidentally shorting something could result in burned wires.

[djway]

This thread gave me a headache (IMG:style_emoticons/default/chair.gif)

I have a drivers side headlight that sometimes does not pop up but the light is on. I found that if I do a quick push on the front of the headlight it will bobb down then up, and away I go. Almost got the finger caught one time though (IMG:style_emoticons/default/wacko.gif)

[john77]

I took the car out last night. Still no conclusive answer.

Warming up on my driveway, lights on, they work fine. 10 minutes sitting there, not a glitch.

I drove 20 feet down the street and they cut out. I tried waggling the switch, nothing.

I turn them off and back on and the lights either come straight back on (and then die) or they flip up, nothing for about 10 seconds, then they come back on, then they die.

Is waggling the switch supposed to have some effect if it’s the switch?

Wiggling the switch may not cause the issue to happen. Likely it's vibration introduced with the movement of the vehicle. Pounding on the dash may get the issue to occur but not guaranteed.

If it is the switch then you have to bypass the switch to test or just replace the switch. I'm not a fan of just replacing something w/o testing first. It could even be the connections to the switch or to the hi/lo beam relay.

Whatever you do to test or replace the switch, remove the negative battery terminal before touching any electrical components. There is no fuse between the headlight switch and the battery. Accidentally shorting something could result in burned wires.

Oh yeah, been there done that and learned my lesson. I fried about 6 inches of the wire into the fog relay by accidentally touching two of the socket terminals when the relay was out. What a royal pita that was splicing new wires into the harness and making sure I found every last piece that was burnt.