# Headlight stuck down and on high beam



## Paul S. z31 (Aug 12, 2008)

Hey everyone, its been awhile since i have been on this forum since my z has been non-op for over a year now yet i still start it and drive it down the street once a week to keep everything flowing. Well last weekend, i was parking it and i noticed the left headlight is stuck down, even when the lights are on. Also if i switch to high beams, they both stay on high beams regardless, even if i shut the car off. does anyone know how to fix this?


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## BeyondBiscuits2 (Jan 18, 2006)

Sounds like a bad lamp motor in regards to the one side staying down. As for the high beams staying on, sounds like a bad lamp switch. Have fun replacing it, it wasn't a pleasant experience for me.


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## Paul S. z31 (Aug 12, 2008)

Still trying to fix this headlight problem, the fuse for the headlamp motor is good. Now im trying to check the headlight relay but i cant seem to find it, anyone know where it is for a 1985 300zxt? The service manual says in the corner by the brake and clutch master cylinders but i didn't see anything. My service manual also says it can be the up hold relay and diodes between light switch and up hold relay. Where are these relays and how do you check to see if they work? i also noticed that once i would turn on my headlights, the headlight retract switch light would come on, does this mean anything?


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## AZ-ZBum (Nov 21, 2004)

There isn't a headlight relay. That's why you can't find it.

Have you replaced the headlight switch yet?


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## Paul S. z31 (Aug 12, 2008)

No i haven't replaced the switch yet. That's the last thing i want to do because that along with the headlight motor are the two most expensive things. That's weird though because in my z31 service manual it is claiming there are relays and even shows pictures of where the headlamp relay should be located. I will try and post pictures of the manual soon. So it is most likely the headlight switch or motor? What about the retract switch? What explains the retract switch light being on once i turn on my headlights?


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## Paul S. z31 (Aug 12, 2008)

Here are the pics:







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## AZ-ZBum (Nov 21, 2004)

The relays are for the headlight motors. That's different from a headlight relay (which there isn't).


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## AZ-ZBum (Nov 21, 2004)

Okay. Forgot about the relay for the alarm. That might be part of your problem.


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## Paul S. z31 (Aug 12, 2008)

Ohh ok, so where can i find the headlamp motor relays because in the last pic it says there are found in the corner where the brake and clutch master cylinders are but i checked and found nothing. Also are the relays for the alarm called theft warning relays, because it says there are two theft warning relays and how does the alarm relay affect headlamp operation?


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## AZ-ZBum (Nov 21, 2004)

When the alarm activates, it flashes the headlights. So there needs to be a relay to handle that.


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## Paul S. z31 (Aug 12, 2008)

Where can i find this alarm relay?


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## BeyondBiscuits2 (Jan 18, 2006)

It is located in the relay box in the passenger side engine bay near the vaccuum canister for the air con / heating system. Mine was black. Your's may be a different colour. If your alarm is going off, pop the bonnet and listen for the relay that is clicking.


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## Paul S. z31 (Aug 12, 2008)

i still don't understand how this alarm relay prevents one headlight from coming up?


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## AZ-ZBum (Nov 21, 2004)

It doesn't. You have an electrical issue. And those are VERY HARD (if not impossible) to diagnose over the internet. 

Is the motor working?
Is the headlight jammed?
Is the wiring connected?
etc.

Grab a multimeter and get to work. No one can do it over the internet for you. This is something you're going to have to figure out on your own. Either that or pay someone to do it.


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## Paul S. z31 (Aug 12, 2008)

Went to the junkyard and got a headlamp motor. The motor is good but still doesn't work, i guess its an electrical issue, and i suck and electrical (don't know anything about it). If anyone is looking for a driver side headlamp motor, selling mine.


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## Paul S. z31 (Aug 12, 2008)

Ok, been trying to read up on electrical all day. I noticed that when i push the retract switch to bring the headlight up, the headlamp relay clicks but the motor doesn't move. However i know the motor works because i tested it on the other wiring harness on the passenger side. I checked the continuity of each wire on the connector on the harness and all seem to be good. I am stumped.


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## jdg (Aug 27, 2009)

Looks like you've isolated the problem yourself right there.
The problem is between the headlamp motor relay and the left headlamp connector itself.
It's either not getting power or not getting ground, or not getting power and ground.


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## Paul S. z31 (Aug 12, 2008)

so is there a way to find out whether its not getting power/ground? I am really bad at electrical, but learning though. What if i just do way with the connector from the harness to the motor?


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## jdg (Aug 27, 2009)

You've got a meter yes?


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## Paul S. z31 (Aug 12, 2008)

Ok, did a voltage test. Found that the r/g (red/green) wire on the harness isn't getting enough volts. This wire runs from the harness inside the dash to the retract switch, to the connector, to the headlamp relay, and then to the headlamp motor. Should be pushing 12v but only getting 3v. I am trying to trace where the wire is bad in the harness but i can't get to it, its too tight in the engine bay and can't get to it. So i was wondering, can i splice the r/g wire from the other harness (passenger /good side) and run that to the r/g wire on the driver side? If this doesn't work, i guess i will just leave both headlamps down and run the lights that way.


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## jdg (Aug 27, 2009)

Don't know about splicing the right side into the left side. Might overload the right side's fuse or relay.
Does the other side get the full 12v?


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## Paul S. z31 (Aug 12, 2008)

yes the passenger side(side that works) get 12v on that red/green wire. Whereas on the driver side, i retested it and its only putting out 3.4v.


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## rickgosk8 (Feb 8, 2015)

I know this is super old but was your problem ever resolved? I'm having the exact same thing happening with mine. Craziness I swear lol


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## Paul S. z31 (Aug 12, 2008)

Stored the z for another few years and now I am working on it again. No I haven't fixed the problem with the wiring. What I did was remove the headlamp motor fuse under the driver side dash and I can turn on my headlights on and off but I can't use my high beams or else they will stay on until I disconnect the battery. You can do this as well as manually adjust your headlights to stay up, down, or anywhere in between. I have mine stay down but it reduces the projection. Good luck with your z


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