I have replaced the dimmer switch, but the problem remains... the highbeams work, but the lows do not. They stopped working one day and I have not been able to figure out the issue. I am heading back out there with my meters, but could use some help in figuring this one out. I hate driving with my highbeams on constantly.

Is there anything between the dimmer switch and the headlights, like a fuse or relay or fusible link? Do they work off of the same power to the dimmer switch or do they use different power sources and what could be between the battery and the dimmer switch?



Later Daze,
Shorty

 

Okay, after a bit of testing, I have come up with:

No power at headlamps low beam connection
There is 6 wires in the dimmer switch connection:
Light Green = Switch (+) fromheadlight switch
Light Green/black = Constant (+) (2 wires into same pin)
Purple/white = Low Beam (maybe???) (2 wires into same pin)
Red = High beam (+) (switched by dimmer)


Does anyone have a link to a headlight wiring diagram? I assume there is some fuse or relay between the headlight and the dimmer switch is bad, because I jumped power from the constant to the purple leads and still no low beams.


Later Daze,
Shorty

 

You are correct in what each wire is for.
Light green is power from the headlamp switch when headlamps are selected.
Light green/black is constant power from the headlamp switch for the high beams.
Violet/white is power to the low beams
Red/orange is power to the high beams

There is no fuse or relay between the dimmer switch and the headlights.
There is, however, the bulk-head disconnect. Cavity 5 of the bulk-head disconnect is for the low beams, and cavity 6 is for the high-beams.

[IMG]local://upfiles/948/C1BAD7777F824754B2650C1FEFE9C3D8.jpg[/IMG]

[IMG]local://upfiles/948/A4809BF21FDA43F4BB8E46C59BA53CA4.jpg[/IMG]

[IMG]local://upfiles/948/09DC924D7E924AE38B298DAC88A005B2.jpg[/IMG]

 

I pulled the bulkhead connector apart when I got the truck and cleaned it with eletrical contact cleaner and then put it back together... and added some di-electric grease aswell... I will pull it apart and test there this evening.

Thanks again!!
Shorty

 

Thanks for the pictures of the diagrams... They helped a lot. I tested all the connectors and go nowhere... until this morning when I left the dimmer switch on low beam and moved the bulkhead around until I heard a tick or click kinda noise and then the low beams started working. I kept wiggling the bulkhead, but couldn't get it to flicker or turn off again. So hopefully this will work for awhile.


Later Daze,
Shorty

 

I'm having the same problem on my 96 3.9l with the low beams. Can anyone tell me where to find the bulk-head disconnect? It looks like there were pictures here but now they're gone.

 

change the dash switch. mine did same thing.

 

Thanks for the suggestion AZ93. Unfortunately that was the first thing I tried and it didn't fix the problem. Now I'm going through and trying to trace the wiring and see if I've got a broken wire or bad connection somewhere. My only other thought is that maybe it's in the hi/low selector switch on the steering column.

 

Hello again, "1998 Dakato" I am still having problems with my headlights blinking on and off, I changed the light bulbs, they were 110 watts, put in stock bulbs that are 55 watts, the light stayed on much longer, about 5 minutes then start blinking again, I changed the head light relayand that wasn't the problem, I am thinking it maybe the dimmer switch on the stearing wheel. Anyone have other sugustions? thanks, John

 

My headlights were only staying on bright and when I would switch them to dim they would not work and the headlight switch in the dash was bad. I changed it out and everything started working again. You would think the dimmer switch would be the one doing it but it wasnt..