Headlight Switch

[‘89Jimmy]

Good afternoon!
I have an '89 Jimmy, that I love driving, but I get some weird headlight malfunctions.

After about 30-40 mins of driving with the headlights on at night, they start to flicker real bad. It's as though a ground comes loose, but the next time I need them, they're just fine again. Knowing that the switch directly powers the lights, (not through a relay) could it be that the switch has a thermal overload protection and interrupts the power such that it looks like it's flickering? I plan on getting a relay system put in eventually, but should I just get a new switch in the meantime?

 

[BoondocK5]

More than likely, a bad ground. But, you gotta put multimeter on the wire heading out to the bulbs, to see if it losing power, or ground.

 

[Blue85]

You could try replacing the switch, or go ahead and do the headlight relay mod, which will remove most of the load from the switch and make your headlights a lot brighter.

 

[‘89Jimmy]

Ok, I found the ground for the driver's side light, and then realized they're not both on the same ground. Given that the both lights flicker exactly in time together, I don't think it's a grounding issue. I'll probably get a new switch and the relay mod, and that'll probably fix it.

 

[imiceman44]

Ok, I found the ground for the driver's side light, and then realized they're not both on the same ground. Given that the both lights flicker exactly in time together, I don't think it's a grounding issue. I'll probably get a new switch and the relay mod, and that'll probably fix it.

You probably will be fine just doing the relay, the switch is still working if it doesn't overheat.

 

[dyeager535]

Ok, I found the ground for the driver's side light, and then realized they're not both on the same ground. Given that the both lights flicker exactly in time together, I don't think it's a grounding issue. I'll probably get a new switch and the relay mod, and that'll probably fix it.

Just thought of something. Isn't the headlight switch grounded through the dash? So if the switch is loose, you run into weird issues?

 

[Blue85]

It does list a ground terminal on the switch, but the diagram shows it as unused. If you look at the diagram above, there is no use for it. I believe the ground is the little metal tab shown at the top of my picture below.

 

[Blue85]

Come to think of it, I recently cycled through all the switch positions without it installed in the dash, to check functionality, and everything worked, that I could see.

 

[dyeager535]

I'll have to check mine. It could be a manifestation of another fault, but I'm certain years back I was playing around with the switch and realized that if it wasn't snugged up against the dash, it didn't work. I'll have to revisit that when I have the chance. Add that to the list lol.