Headlight problems

[orange-Z]

Went to pick my wife up at work the other evening (she had been there 14 hrs and was keen to get home) and the 260z didn't have any instrument lights.  All other lights worked ok and there was no other vehicle available so decided to go anyway.  Got her just fine but she immediatly noticed the lack of instrument lights and made the usual comments about my great little machine.  Got half way home on a dark rural road and both headlights went out - but the good news is the instrument lights came on!!.  Pulled over to the side once I could see a little bit.  Wife is really impressed now.  Checked fuses and all ok.  After some mucking around I found that the tail and brake lights were ok and the fog/driving lights worked so eventually got the car and my wife safely home.

 

Now, the headlight switch checks out ok, the fusible links by the brake booster (green and black) and the black fuse holder in the engine bay are ok.  I changed out the passing and dimmer relay with another from my parts car and it didn't make a difference.  I don't know if the replacement relay is working.  I tried to check the relay out as shown in the service manual but can't sort out the terminal numbers.  The manual shows the terminals at the other end of the wiring harness which I can't easily get to.

 

The wiring diagram in the service manual shows a brown fusible link but I have not been able to find it.  Can anybody tell me where it is located and also what else I should check.  The car is a 1974 model 2+2.

 

Thanks for any help.  I don't understand what could cause first the instrument lights not to work then for them to turn on when both headlights (high & low beam) go out.

 

Alan (In the dog house again)

[RB30X]

Have you played/touched/worked on anything lately or is this out of the blue?

 

Its almost something like some relays in backwards and when your headlights went out the dash got voltage etc.

 

I wish I had the internet in my shed/doghouse.

[crazed]

Pull off the steering column shroud and physically touch/jiggle the soldered connections on the light switch. Have heard that the soldered connections come adrift with age. May look ok but you can't tell till you actually interfere with em. Worth a try if everything else you've mentioned checks out.

[Zedman240®]

On a 260Z I had, headlights use to flicker on and off while going over bumps. Traced it back to dodgy connections on the fusible links. They may look okay, but remove them and clean them thoroughly and check again. Fuse holders sometimes play up but rarely together at the same time.

[NZeder]

My 260z no longer has the passing relay (remove when I got the car 16 years ago). There is a plug on the end of the relay connector that loops the two red/black wires together = relay bypassed. That is all that is needed to bypass the passing/dimmer relay. So you could try that and see if they both are at fault ir if all is well after the bypass could be the relays at fault. I am in the middle of upgrading my fusible links and headlight wiring on the 260z to include headlight relays to remove the full current going via the switch on the colume. I have the mods mapped out and when the nz festival of motorsport finishes next weekend I will be able to spend time in the shed again. I will post what changes I make and a diagram etc

[chris240]

I had the exact some prob & tracked it to my headlight wire within the instrument stalk..basically the start of the chain.

the solder that connected the headlight / instrument wire to a circuit board thingy had called it a day, & needed to be re-soldered...Im positive there is a thread under electrics in the forums on this.