Blowing Fuse 5amp instr/lps

[Justin Fleming]

Trying to circle back to this fuse blowing, It is a 5amp fuse and it says instr/lps this controls the back lighting in the dash. What I have noticed is that I can put new fuse in, pull the head light switch out and it is ok, start the truck, still ok. I can dim it left and right still ok, but when I make it far enough to just about turn on the dome light (that notch in the switch) that is when it pops the fuse. This is repeatable. The dome light comes on and works. Any help as to where I should be looking to track this down. My first thought is possibly a faulty head light switch??

 

[cuervo]

Do you have the wrong dome light in there? There are a couple of different pole configurations on the dome light. I have an 83 1500 gmc pick up that has a white courtesy light over the outside back window that kept blowing the fuse. It turned out the OP had the wrong type bulb in there.

Possibly a cut or bare wire under the headliner?

 

[Justin Fleming]

Do you have the wrong dome light in there? There are a couple of different pole configurations on the dome light. I have an 83 1500 gmc pick up that has a white courtesy light over the outside back window that kept blowing the fuse. It turned out the OP had the wrong type bulb in there.

Possibly a cut or bare wire under the headliner?

I dont beleive it to be a dome light bulb issue as the truck has been fine for quite some time....I suppose there could be a possibility of a bare wire under the head liner, but would think that it is unlikely....

 

[dyeager535]

If dome lights work with the door switches, don't see how it can be a wiring issue with anything other than the headlight switch itself.

 

[Justin Fleming]

I will have to do some digging and see if I still have a dimmer switch from other scrap outs. I found some wiring diagrams for a different year but I am sure its similar wiring, but I am in agreement with you that it is likely that the dimmer switch has a issue when there is a contact closure just at the peak of bright and turning the dome lights on.

The dome light works fine from the dimmer and it work when opening and closing each door fine....

At a -23 degrees today I think it will have to wait a few days...

 

[dyeager535]

I guess you could unplug the switch, and check for continuity to ground as you rotate it to dome. That would probably tell you if there is a short going on internally.

I've not had this problem with the headlight switches, but I've had them fail before, the last one the ceramic resistor housing just fell apart, and it was apparently a brand new aftermarket piece.

 

[Justin Fleming]

Still blowing the 5 amp fuse after replacing the head light switch. It is certainly intermittent as the last time I replaced the fuse it was good for a few night and then pop the fuse again.

 

[45acpJr]

Is there anything else tapped into the dome circuit? If I recall correctly the cig lighter is on the same fuse, any after market accessories like a cb or anything tapped on to that circuit?

 

[Justin Fleming]

Is there anything else tapped into the dome circuit? If I recall correctly the cig lighter is on the same fuse, any after market accessories like a cb or anything tapped on to that circuit?

Nothing all original...

 

[45acpJr]

If it was me I would disconnect the dome light (there should be a harness by the driver seat belt area), disconnect the gauges, and disconnect the cig lighter. Try to replicate the problem, if it doesn't blow reconnect one item and repeat untill you blow the fuse. I always try to narrow it down whe trouble shooting.

 

[4xcrazy]

Horn, dome and cigarette lighter have their own fuse and are all on the same one.. It's not that 5 amp thing.

 

[45acpJr]

Horn, dome and cigarette lighter have their own fuse and are all on the same one.. It's not that 5 amp thing.

Yup I totally missed that, I think that is just the power for the bulbs in the cluster, maybe a short at one of the bulbs?