Headlights dim when I apply the brakes and fuse blows? HELP

[The White Noise]

So first off I am sorry if this has already been discussed I looked and didn't see anything, next I'm new so sorry if I don't discribe something right.

 

Alright so I have a 88 Comanche with 2.5 with 4 speed 2wd no ac,ps,pw,pd nothing! Just a base model Comanche. I have recently installed the 99 Cherokee front end and when I turn on my lights they all come on and work fine but when I start driving and apply the brakes the headlights will dim slightly and my parking light fuse will blow? And my gauge light shuts off and all my running lights shut off? Brake lights, headlights, and blinkers all still work?

 

Please help!

[Blue88Comanche]

:popcorn:

[carnuck]

Battery loose and hitting fender/hood? Short in brake lights? Missing ground strap from body to battery? (one to the motor doesn't count)

[Eagle]

Obviously, something about the way you connected the wires for the '99 front clip isn't compatible with the original chassis wiring in your truck and you have a short circuit. That's the easy part -- the trick is to figure out where.

 

I think I would begin by removing ALL the light bulbs in the front -- the headlights, parking lights, and side markers. Then try stepping on the brake and see if the fuse blows. It probably will, but -- if not -- replace one bulb at a time until it blows, and that will tell you what circuit to trace.

 

Since shorts typically occur upstream of devices (light bulbs, in this case), the above may not show you anything. If not, then the next step is to unplug the connectors feeding each light bulb from the harness. Step on the brakes. Hoefully no blown fuse. If that works, plug in one light at a time until you find the one that causes a blown fuse, then trace that circuit.

[The White Noise]

So thanks for the info sorry it's taking so long for me to get back I work a terrible schedule and I hardly ever have time to work on my truck, but I'm goin to work on it today and try what u said eagle, hopefully I'll find the problem.

 

( ive put a higher amp fuse in for the time being, and it still dims but doesn't blow fuse so thats how I've been driving it)