A short will usually blow the fuse the moment power is applied. It sounds like an over current issue. Either the bulbs are drawing more than 25amps or more power is being asked for than can be delivered and is causing the circuit to overheat and blow the fuse. If it is possible I would switchout to a larger guage of wire. The longer the run the larger the wire should be.

I would also take a multimeter as suggested in another post and start taking some readings. Start checking to see if you have continuity to ground even when you aren't supposed to. Measuring for current is a little hard some time, the meter need to be inline with the circuit, resistance and voltage are done in parralel.

A simple cicuit like this should be easy to isolate since you have access to the entire thing. Good Luck

 

I'm thinking wiredawg might be on the trail of this one with the small diameter wire.

 

It is most probably the factory wire size being too small. Here is a standard chart of rated amperages per wire gauge. This is only a guideline as many other factors determine the amount of current the wire can handle.

h t t p://www.interfacebus.com/Copper_Wire_AWG_SIze.html
and
h t t p://www.powerstream.com/Wire_Size.htm

 

I'm assuming you purchased the lights new....assuming that it the case why not just call KC and take advantage of the 27 year warranty...Why should you have to go dismantling the harness and trying to diagnose there f-up (assumng it is there error)

 

I really doubt that the harness is bad.

 

I payed duty, tax plus shipping.. i don't want to pay shipping, tax and duty again this kind of stuff pisses me off there brand new and should work when installed. I e mailed KC but you guys are much faster.

I have installed many electrical things in my life in the past and had no issues. Out of about 15 items I have purchased for my jeep 8 things had to be sent back for warranty its getting old and costing me money.

 

Have you tried just using them with the truck running or are you testing them with the truck off. The truck powered off is only putting out around 12.8 which takes alot more current to power them lights then 14.4v running. Give that a try.

 

yep i tried on and off and on the batter by itself with nothing else attached. no change. Tomorrow i am going to check the inside of the lights and get a new relay if i dont find anything. i will lett you guys know thank you

 

I don't think a couple of volts less would make a light draw more amps. If that were true, you'd blow fuses all over the place as the battery wore down from leaving stuff on.
In fact, it's the opposite. As the voltage drops, LESS electricity goes through the filament. That's why they become dimmer. With the resistance remaining the same, and the pressure (volts) becoming less, fewer electrons (amps) will flow.

 

I checked the wiring inside the lights everything looked good. but i added extra coverage on the connections just in case. Then I added a 25A fuse instead of the 20A that it came with and everything is fine. I think it was the fuse. the Relay is rated for 30A and they sold it with a 20A fuse. i believe there was to many amps for the fuse so it was blowing. Using the 25A fuse solved the problem