High beams only

[Franks]

So I have a 92 k1500 with high beams but no low beams. I have the 4Hi mod and the relay is good. And ideas where to go next?

 

[Eveready]

First step would be to jump power to the low beams and make sure that the bulbs are good. Most likely they are. I suspect you have a bad connection or a cold solder joint in the wiring for the 4 hi mod. If you restore it to factory, determine that it works and then carefully re-install you likely will fix the problem along the way.

Good luck and let us know what you find!

 

[Franks]

I’ll see if I can figure it out. I didn’t install the mod though.

 

[Gambles]

Did you buy a harness that tied them all in or what? There should be 3 relays somewhere near it. one that feeds lows, one that feeds highs. then the last one which, with high beams it also pushes through triggered by the highs and does a relay pass through to still energize the low beams... you can also do it with just one relay, but i don’t prefer it personally... also did they work before or did someone just do the 4 high mod and say there ya go and you go

 

[Franks]

It’s one relay and the mod was on the truck when I got it

 

[delta_p]

If it one relay, the relay is probably tied into the fuse box under the hood. I am only guessing, but it would be set up as the low beams are straight through nothing to with mod. But in high beam, the high beam wire is tapped into to trigger a relay that then operates the low beams from B+ at the fuse box, or maybe off the battery if they routed it there. So if the low beams don't work at all, it could just be a low beam problem, like bulbs, fuse, open circuit or something.

 

[df2x4]

I would be suspicious of the headlight switch as well if all of the above checks out.

 

[Franks]

I would be suspicious of the headlight switch as well if all of the above checks out.

headlight switch as in the one that turns on the lights?

 

[kennythewelder]

headlight switch as in the one that turns on the lights?

Yes. A test light is your best friend in tracing down an issue like this. It takes very little current to trip a relay. There is really no need to undo the 4 high mod, unless there is an issue with it. Check with a test light at the low beam headlight connector for power. If there is none, then just work your way back to the switch with the test light. If you dont have a test light,any of the auto parts stores sale them, and they are not expensive. Maybe $10 or so. Also check the fuses if you havent yet.

 

[df2x4]

headlight switch as in the one that turns on the lights?

Yes sir.