260z Headlamp Wiring Help

[Ryan_260z]

260z Headlamp Wiring Help - WIRING TEST RESULTS NOW INCLUDED

UPDATED AT BOTTOM WITH SOME TEST RESULTS




Hello yet again.

Im having some trouble wiring up my headlamps. Ive got 4/5 wires coming out the side of the car and ive got 4 wires sticking out the back of the lamp (1 Earth Wire for both Sidelight and Lamp Earthing - Sidelight Positive - Main Beam Pos - Dipped Beam Pos).

I was using the method of first finding the earth that came from the car - managed that - plugged it in.

Then turning the stalk to sidelight then trying to find the positive supply coming from the several wires - however there wasnt one. I managed to find a positive for the dipped beam but again nothing for the main beam. So its a bit all over the show. Now im sure i thought i heard something about the wiring on the headlamps being a bit strange and that they were permanently live and then the earth was used for the switch. Is this right? Can anyone help me out with this one. Most greatful as always!!!

Ryan

 

[Mr.F]

Headlamps are earthed back at the switch, not at the bowl end. The sidelights are earthed at the lamp.

 

[Dale]

Try this wiring diagram Ryan. Hope it helps.

 

[Mr.F]

Nice idea, but beware that the diagram is:

a. For USA models - we don't have marker lamps arranged like that and the indicators will be wired differently.
b. The combination switch is in two distinct halves. Also no combination switch ground is shown nor the grounding link between the two halves.

Try the attached scan from the Nissan manual - more technical, I know, but correct...

 

[SKiddell]

A good percentage of headlight issues are rooted in the 30 year old "combination" switch. I've refurbished a number of these and most of them suffer from the same fault. Inside the switch body a pin cam bears down sequentially on 2 plastic nibs (one for side lights, one for main) these nibs in turn bear down on copper fingers thus completing the circuit to earth. The problem lies in the fact that shockingly, the Japanese couldnt design a plastic that could withstand 30 years of cycling 100,000's of times and consequentially the plasic wears down, this in turn reduces the pressure on the contacts and hey presto no circuit. A couple of solutions are

Invent a plastic that never wears out.....nope
Rewire your entire lighting system....unlikely

Alternatively
Swap the nibs over, (sometimes works as a temporary fix)
Make new nibs out of various household items (A "bullet" electrical connector end works well).
The end off a ball pont pen (the end that you click endlessly when bored to death watching powerpoint presentations by the sales team)
Or the old nibs can be "built up" using epoxy

Beware though, when disassembling the switch, microscopic springs will attempt to depart, never to be seen again.

 

[Ryan_260z]

Thanks for the advice everyone im still working at it - i thought id try a logical approach to see what exactly was happening at the wires.

With the lamps completely diconected and the wires just sitting there i tested each side in turn. I started with the stalk in the off position and then tested each wire to see what it was doing, then switched to sidelights and did the same and so on. These are the results i got... Does this mean my wiring is capput or i have the problem as mentioned above. I would say that before being diconnected everything was working as it should and i havent altered anything i dont think.... Also does the car have to be running for the sidelights to work? If anyone can make something of these results i would be pleased to know! Where there is a gap it means the wires were not showing as being live or earth.

Thanks again.

 

[Ryan_260z]

Ok ive worked out that the sidelights and the indicators should share the same negative. I think ive also figured out that the main lamp stays positive throught during dipped and main beam and then the switch controls earthing to the main and dipped. From what i can tell im not too far off, it just seems that the sidelight positives have dissapeared. Ill have to see if i can trace them back - its a bit of mission with the wire colours all over the show. I just hope i havent made a boo boo in the fact that i know that the sidelight and lamp have a wire that is joined together on the plug (this is how it was when i removed it and just left it so). I should be able to use this wire to send the earth ive found down. eek, what a mess.