# Headlight diodes



## Lynx88 (Feb 7, 2005)

Does anyone know where the headlight diodes are?


----------



## Lynx88 (Feb 7, 2005)

I guess I should mention that I need to know the diode locations for a 300Zx Turbo from 1985.


----------



## Zen31ZR (Mar 24, 2004)

Diodes? You mean the fuses or the relays? I'm not aware of there being diodes for the headlights.... What is the problem.


----------



## Lynx88 (Feb 7, 2005)

The problem is that my low beams went out again... I have tested the switch, the relays, the fuses and the fusible links with a multimeter and I know they all work. I know the lights are not blown because I send power to them directly from the battery and both high and low came on. According to the wiring diagram, there is a diode connected to the headlights, but the way it looks it should still come on without it. Anyways, I figured I would check it first before I go looking for broken wires. 
If you have any ideas let me know. If it helps, I just got done putting the intake collector (the thing just underneath the 3000 turbo plate) back on. I had to take it off because of a leaking fuel line that needed replacement. The lights stopped working just after that.


----------



## Zen31ZR (Mar 24, 2004)

Be odd for _both_ sides to go out at once. I think the diode just balances the voltage received by both sides, keeps one from being brighter than the other. I can't say for sure it's function. Seems to me more likely it would be the low beam relay. I know you say you tested it, but try swapping in another anyway....


----------



## asleepz (Feb 24, 2004)

Sounds like either the relay or the headlight column switch may be bad.


----------



## Domdogg123 (Nov 12, 2004)

♣AsleepZ♣ said:


> Sounds like either the relay or the headlight column switch may be bad.


2nd the vote on Bad Switch.


----------



## Lynx88 (Feb 7, 2005)

I tested the headlight relays by switching it out with the other black one in the relay box. After that I tested it with a multimeter just to be sure. Also both the low beams didn't both go out at the same time, it was the right one first then the left shortly after (next day). As for the headlight switch, I am 110% sure that it works, I put in a new one not to long ago to fix my light problem last time, and I did test it...

Tomorrow I plan on running my own wire for the low beam... I figure why not just by pass all the junk Nissan did, not to mention I would know exactly where everything is if it goes out again.

If that doesn't work... I'll be back.


----------



## blownb310 (Jun 10, 2002)

Lynx88 said:


> I tested the headlight relays by switching it out with the other black one in the relay box. After that I tested it with a multimeter just to be sure. Also both the low beams didn't both go out at the same time, it was the right one first then the left shortly after (next day). As for the headlight switch, I am 110% sure that it works, I put in a new one not to long ago to fix my light problem last time, and I did test it...
> 
> Tomorrow I plan on running my own wire for the low beam... I figure why not just by pass all the junk Nissan did, not to mention I would know exactly where everything is if it goes out again.
> 
> If that doesn't work... I'll be back.


 I fixed a friend's Z31 for this same problem. It was a bad switch. Did you find anything yet?


----------



## Lynx88 (Feb 7, 2005)

I never found the diode... I did run my own wire and that fixed the problem. We found out that the right blub had burned out and the left had wiring issues. I ran the wire from the left to the switch and tried it again. It still didn't do anything. So I took the multimeter and check the voltage on the wire that is suppost to connect to the left headlight, it read zero volts. So the wiring problem was somewhere between the battery and the switch. But instead of tracing those wires, I just made both headlights run from the same hot wire... So it's fixed for right now...incorrectly, but it works.


----------

