Diagnosing no headlight with relays 260z

[882993md]

I purchased my 260z (build date 8/1974) with the headlight upgrade with separate relays for high, low, fog, and wash. I have working brake lights, hazard, and turn signals.

I tested the wiring at the combo switch by testing the white/red wire with a test light and it has voltage  (so wiring from fusible link is ok). 

With the headlight switch turned on I tested the solid red wire with the test light and it has voltage so that means my switch is good.

The headlight power is coming off the positive starter bolt.

Would I now test to see if the relays are bad?

Howard

1974 260z

[Kurbycar32]

If you suspect a bad relay: Pull the relay then Google the test procedure for that model. Generally you apply voltage to one pole and it should make a click then route power to another pole.

Here is a general example but you need to find the diagram for your specific relay
http://www.wikihow.com/Test-a-Relay

Sent from my SM-G930T using Classic Zcar Club mobile

[7tooZ]

I usually start by checking the grounds. If good grounds have someone work the switch while you put a finger on the relay. You will feel the click and usually hear it. Check all four relays. If some work and some don't move the working ones over. If still not working check the power from switch is reaching the relay. If the relay is working the issue is in the wire between relay and the lights. Recheck the grounds. Check to verify constant 12v is reaching the relay. Check the plug that routes the power from the original light harness.
Seems odd that the only issue is the high and low lights. I suspect the switch or bad ground to the relay panel. Good luck


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[Zed Head]

2 hours ago, 882993md said:

I purchased my 260z (build date 8/1974) with the headlight upgrade with separate relays for high, low, fog, and wash. I have working brake lights, hazard, and turn signals.

I tested the wiring at the combo switch by testing the white/red wire with a test light and it has voltage  (so wiring from fusible link is ok). 

With the headlight switch turned on I tested the solid red wire with the test light and it has voltage so that means my switch is good.

You're saying "the" headlight upgrade but it looks like "a" headlight upgrade.  In other words, it's not one of Dave Irwin's kits.  Just to be clear.  So you don't have a reference for how the work was done.  There are lots of different ways to add relays to the system.

It looks like you're not aware that the high and low beams are controlled through a switch that controls the path to ground.  Without the ground through the high/low beam switch no current will flow and the lights won't light.  The switch is at the base of the turn signal stalk.  Could be it's just unplugged at the steering column.

[sweatybetty]

delete

Edited February 8, 2017 by sweatybetty

[882993md]

6 hours ago, Zed Head said:

You're saying "the" headlight upgrade but it looks like "a" headlight upgrade.  In other words, it's not one of Dave Irwin's kits.  Just to be clear.  So you don't have a reference for how the work was done.  There are lots of different ways to add relays to the system.

It looks like you're not aware that the high and low beams are controlled through a switch that controls the path to ground.  Without the ground through the high/low beam switch no current will flow and the lights won't light.  The switch is at the base of the turn signal stalk.  Could be it's just unplugged at the steering column.

I have no documentation on the upgrade but I checked the fuses and they are ok. I also tested the relays and they are ok too. 

This is a picture of the wires below the steering column. I have two black wires not connected. I have to look them up in the wiring diagram. I also see another relay. The relay base grounds out on the steering column, and the other pin goes to that white double connector. 

Howard

Edited February 9, 2017 by 882993md

[Mikes Z car]

My 240Z car with relays had no hi/low headlights one night and the problem was what Zed Head outlined, I had no ground from the high/low switch.  I don't know if that switch can be fixed, I couldn't figure out how to fix it back when I was doing switch refurbishment but I put in a backup switch that performs the same function that sticks out from under the console at the bottom.  Haven't needed it since that one night though. 

 Now if I could just figure out how to turn bold off.

Edited February 9, 2017 by Mikes Z car
add relays and info on refurbishment

[Mike]

5 hours ago, 882993md said:

Just saw this post and image above.  I am not sure what is going on with that wiring, but, it looks like you have big problems.  The top white wire needs to be replaced.  Do you have power at the headlight when the switch is turned on?  If not, follow the wiring back one step at a time to see where you do have power.  Check both sides of the fuses.

[Patcon]

I agree with Mike some definite issues there. Don't you just love PO's wiring "skills"

[882993md]

I connected the ground wires that were hanging loose and I have partial headlights-high beam only. (I connected the ground just like in these pictures).

I double checked the 10A fuses on both hi/low beam relays and the low beam was blown. Easily solved I thought. I replaced the fuse and as soon as I switched on the lights the low beam fuse blew immediately.

I have attached a rudimentary drawing of my headlight relay setup. I'm wondering if anyone may be able to identify a wiring error. Thank you.

 

 

Edited February 21, 2017 by 882993md
Add/delete file