CAUTION: I know nothing. Refer to factory service manuals and other experts before doing this. This "tutorial" is just my experience . Research safety issues as I know nothing about safety.

work-in-progress. input welcome.

1.Check your fuses(at least 3) and bulbs first.2.Move relays 1,2, and 3 around to see if symptoms change. If symptoms change you know your problem is the relays. 3.You might substitute in a known good light switch(sw)or repair switch per this article: Repair light switch4.You need to be a good electronics person to solve this logically.5.Start by seeing if ground or 12V+ is getting to light bulb.

Headlight switch and headlight timer(click twice to max):



Left retraction motor, left headlight, 4 retraction relays:







Physical location of headlight switch:



Relay box by battery(contains 1 h/l relay and 2 headlight(h/l) fuses)

Relay box by air filter(contains 3 h/l relays;all the same)

Links

Light wont pop up thread

Repair light switch

Modified by vancouverbc at 2:23 PM 1/17/2009
Modified by vancouverbc at 7:45 PM 1/31/2009

hate to ask but what happened to bring this up?

180fan wrote:hate to ask but what happened to bring this up?

Just alot of people having trouble with the headlights.

lol I was about to say, jeez your car's got alot of problems even by s13 standards ha ha ha

Thanks for all the good info....my 240sx vert headlights have been giving me intermittent trouble for a while. Now I think I know where all the relays are. Great photos. You dont have the Nissan part #'s for the 3 that are the same do you? I suspect it is one of those. Sometimes my headlight is lazy on the right side. I spin the motor manually and I hear a click from the box near the intake snout....up it goes. Also, when the headlight is stuck down, I have heard the same click if I push the headlight up dash switch although w/o headlight movement. Who knows....

The horn relay is not identical to Retract 4. Retract 4 is a 6 pin relay while the horn relay is a special 3 pin relay.

Retract 3 and 4 are the only relays that affect the motors. Retract 4 helps the motor go up, while retract 3 makes it go down. An easy way to test if it's the lighting switch keeping the motor from going up (which is likely as the switches do burn out after so many years):1-Remove the grey Retract 4 relay2-Turn the lighting switch to "on" (low beams)3-Take a test light and check pin 2 for powerSee the arrow pointing to Pin 2? Find it's corresponding plug on the relay base.

If your test light lights up with the lighting switch "on", then you have a good switch that's supplying power to the relay. if not, you isolated the switch as a possible problem part.

You can check Retract 3 in similar fashion.So long as the lighting switch is turned "Off", pin 1 should be hot when you test it with a test light. The headlamp timer is what grounds out this relay to power the motor to go down.

Also, the TCU can be problematic as well. A lot of sleepy eye modifications actually damage the TCU by frying one of the circuit pathways inside the unit. Soldering a new wire in place of the circuit board path can solve the problem.

Thanks VancouverBC - I was looking for something like this!!

Hijacker - this is amazing - Thanks!!

Thanks. I appreciate it. The fsm has a ton of wiring diagrams that show all the conditions that the light system can be in. It is just like a computer program.

FSM?My car came with no Factory service Manuals - is there another place I can find info?For example - headlights don't pop up - does the switch on the dash need to be on? (it doesn't work either). I'm in the process of testing this circuit but not sure how it's supposed to work.Thanks again.

Andy65 wrote:FSM?My car came with no Factory service Manuals - is there another place I can find info?For example - headlights don't pop up - does the switch on the dash need to be on? (it doesn't work either). I'm in the process of testing this circuit but not sure how it's supposed to work.Thanks again.

there is a link to 1989 fsm in my signature. that would be applicable to your 1990.

Thanks VancouverBC,I was reading it without even knowing - I'm covered.Have a good wknd.

Yay, thanks for the info guys. I replaced my headlight steering column switch and all is working! Before lights wouldn't retract down, and only the left headlight worked unless I had brights on. I bought a used $35 switch off eBay and it fixed me right up. I spent a few hours on this after swapping relays, diodes, timer control unit, etc.