99CherokeeSport

Hello there im new to the site and hope someone can help me. I have a 99 Jeep Cherokee Sport 4L. Whenever my jeep gets wet or frozen i seem to blow the brake light fuse. This has been happening for the last few weeks. It also seems my rear defrost isn't working anymore, could this all be linked together? I pulled the rear defrost switch out to check the bulbs inside and they look good, but the light does not go on when the switch is pressed. This really sucks for me as when it comes to electrical i do not no F/A.

Howler_GT

You will be glad to know that the fuses are doing thier job and popping before any electrical fires or burning happens.

I do not believe the two problems are related.

Lets start with the fuse problem.
Somewhere between the brake light switch and the bulbs there is a short. An exposed wire or something of the sort.

Start by pulling the brake light sockets out (after pulling the taillights)
Inspect the bulbs and sockets. Make sure the 1157 (or equivelant dual element bulb) in installed correctly and that no-one has forced the bulbs in the wrong way.

Next you should perform a Continuity Test
With all lights OFF. Use a multi-tester and check the connections (contacts at bottom) inside the sockets for grounding. Touch one terminal of tester to connection, the other to a good ground. Do not test the contact on the side..that is a ground.
If the tester shows any reading you have found the culprit. Somewhere along that wire there is a damaged area.
Perhaps the wire got kinked or snagged on a sharp edge or someone installed a screw somewhere that pierced the wire.


As for the defroster:

Was it ever working for you?
Check the fuse? (I know...it sounds dumb. But I have to ask.)
Inspect the glass grid on the hatch glass.
There are two wires soldered to the grid on each side.
Driver's side is the incoming power and the passenger's side is the grounding wire.
Make sure BOTH are still attached to the grid.

As for the switch...
Did it smell burnt? This is a common problem.
A quick trip to the j/y can net you SEVERAL switches cheap.
Try putting in a different switch and see if that remedies the problem.


Hope this helps or at least points you in the right direction.

storm101

I agree with the previous reply, but also on my 99 and one other buddies 00 i noticed where the wiring goes in thru the hatch (open it up and look where the hinges are) that the rubber boot and wiring is going to crap from opening and closing the hatch, i would take a peek up there too, my buddy had to rewire his and i remember he lost power to all sorts of odds and ends back there, if the boot is ripped you should be able to see the wiring and also see any broken wires if they exist there

Figured i would post it up for a easy spot to at least rule out