Hello all, I'm having issues with the headlight switch dimmer in my 03, everytime I turn on my headlights fuse 18 blows, so I have no instrument lights, pretty much everything in the dash is in the dark. I put in another headlight switch and it still blows fuse 18, now I did some testing and if I unplug the dimmer it won't blow the fuse so is something in the dimmer wiring that's causing it. I tore apart my dash today with no luck, checked all radio connections and nothing it still blows. I'm really lost here don't even know where else to look anymore. By the way my tailights still work and so my interior lights as far as the dome and door swiches still light up. Any suggestions? Thanks in advance.

 

I wii hazard a guess. Replace ur cluster.

 

You say you replaced the headlight switch - have you tried a different dimmer switch?

 

The dimmer switch is part of the HL switch...

 

Aren't the two circuts separate from each other. Dimmer only dims the cluster lights. Turning on the headlights has nothing to do with dimmer.

Sounds like you got ground out somewhere or a short somewhere.

 

Yeah, I'm thinking the same thing, and they are. I blew my fuse out once and the hls did work, but the cluster lights didn't. Problem now is tracking down the ground, which Isn't too easy...

 

U have bad microprocessor in cluster probably. U can pull several relays to help minimize the circuits. High and low beam relays. The ground wire under the cluster is blk/grn I believe. I believe it is involved with other circuits under the dash.

 

No I Haven't but I did find out that if I unplug the multi-function switch the fuse won't blow and instrument lights do come on so I guess the switch is shorted for some reason.

 

Interesting because my SES light does not light up even when you first start the truck, I wonder what could've caused it to not work, maybe previous owner who knows?

 

If this is the case, can the cluster be repaired or will I have to buy another cluster?

 

I'd try to repair it if I could. Its not gonna be an easy problem to deal with from a PATS cluster swap.

If thats what it comes down to, you're gonna need to find a speedo shop. It will need to be a one day thing as the truck will not run without the cluster, and the cluster nees to be flashed to the truck.

 

Unplug an continue looking. Even trailer wiring.

 

Well is not the dimmer switch, I got another one from a scrap yard and fuse still blows, so I'll move on to the trailer wiring thanks guys.

 

OK, don't forget this. http://www.aboutautomobile.com/Compl...er+Dash+Wiring

 

Replace the fuse with solid wire, then wait and see what melts.

Yes, that was a joke, please don't do that.

I don't think it's the cluster though. There is not a lot of stuff in there that can draw that much amperage. Even if a bulb is shorted, it wouldn't blow the fuse. Something is definitely shorted to ground. I think you have it with the multifunction switch.