Hi everyone, this is my very first post on this forum. I come from a background in diesel Mercedes (W123s) and have done every job imaginable on those cars. I also have my grandpas 1964 Oldsmobile cutlass that I am restoring. Long story short, working on cars is nothing new to me and I'm glad to finally make an account here.

The issue I'm running into is that my 1988 Toyota's tail lights won't come on when I turn the stalk to the on position. The dash lights don't come on as well and I assume they are connected. This started a few months ago simply one day I turned my lights on and noticed the dash didn't light up. I reflipped the stalk and magically the dash lights came on. I figured it was a worn out switch but I was driving the other day right before dark and I had my lights on (the dash lights and tail lights weren't on as per the issue) and I shut my blower fan off and magically the dash lights turned on, as well as the tail lights.

I have owned this truck for about two years and have done a bunch of maintenance to it but I am not so well versed in these trucks just yet. So instead of going to town on the truck I figured I'd ask here first if anyone has any ideas. The fuse is fine so I presume there is a short somewhere or a corroded ground somewhere. I have no clue where to look first though.

Thank you

 

Clean ground G(left kick panel) and B (right fender).

 

Excellent Move! Welcome to the forum.

By lights, you mean headlights, correct?​​​​​
How about front clearance lights?
Your answer to above will narrow down where to look.

IF ONLY TAILS, CLEARANCE, DASH ARE AFFECTED:
Could be Losing 12V along red line: Relay loose in socket, fuse lose in holder, corroded connections, etc.
Could be losing ground along green line below... bad dimmer-combo-stalk switch contact is most likely cause of this. To verify, jump pin 11 to pin 10 and see if problem occurs.


1988 schematic says that ground point F is in "Left Back Panel" That is not clear to me, although I've seen a ground point in the left body panel cavity.


I am not sure what schematic means by "Left REAR Panel". Could be rear left body panel, OR left kick panel by driver's foot.




IF HEADLIGHTS ARE AFFECTED:
Problem is in combo-stalk switch pin 10 and/or its connection to ground point C on inner front left fender.

 

Thanks for all of the advice everyone.

The new relay came in the mail today. I popped it in and everything now works as it should: