Question about 2004 Jeep Grand Cherokee
On my 2004 Jeep Cherokee, I had two of the three brake lights burn out. The top and the one on the passenger side. I replaced the top one and it worked fine. Then I replaced the passenger side one and now all of them are not working. Is this a fuse or some kind of switch that needs to be replaced?
It is usually the brake light switch that caused all the problem that is located down by the brake pedal on the pedal arm and can be removed and tested with a 12 volt test light, if its bad just replace it there's no repairing those at all, that was a real common problem with some of the Chrysler products, its not an expensive part though and very easy to replace.
The brake lights are always hot, that is to say they are powered all the time, key on, off or in your pocket. The best way to troubleshoot an open is from the battery back. In the typical brake light circuit power goes from the battery to the fuse box to the brake light switch to the bulb and then to ground. Take the test light and put the clip on the negative battery terminal and touch the point to the positive battery terminal. This does two things, it checks the battery for voltage and it insures your test light is working properly. There's nothing worse then the feeling you get after spending an hour looking for a problem and finding out the bulb in your test light is burnt out.
Next you check the fuse. The fuse box is usually marked with the fuse amperage and the circuit. For example, Brake lights 10 amps. If the fuse box is not marked, it will be in your owners' manual. Clip the test light to a good ground and touch the point to each side of the fuse. If the light lights on both sides, then the fuse is good. If it doesn't, then the fuse is bad. Replace it before you continue. If neither side lights up, you have an open between the battery and the fuse box. Repair the wire before you continue. Now by looking at the wiring diagram we see from the fuse box it goes to the brake light switch. The brake light switch is a simple on-off switch. When the brake pedal is up, the switch is open. When the brake pedal is down, it closes, completing the circuit. Touch the test light to both terminals of the brake light switch, one side will be hot and the other side will not. If both sides are hot then the switch is not opening and the brake lights are on all the time. As with the fuse, if neither side lights, you have a broken wire between the switch and the fuse. Repair the wire before you continue.
Now push the brake pedal down and touch both sides. Both sides should be hot. If they aren't, the brake light switch is not closing and is no good. You'll need to replace the switch before you go on testing. Looking at the wiring diagram we see the wire goes from the brake light switch to a connector in the back of the car. Go back there and locate the connector and unplug it. Now you see there are 5 wires in that connector. Which one is the brake light wire? Looking at the wiring diagram tells us that the blue wire is the brake light wire. So touch the test light to the blue wire and if it lights, you have power to that point. If it doesn't, then you have an open between that connector and the brake light switch. Repair the break before continuing.
Now we see it goes from that connector to the brake light bulb socket. Take the bulb out and touch the contact inside the socket with the test light. If it lights, then you have power up to that point. Put the bulb back into the socket and from the back, pierce the black (Most automakers use black for the ground wire. German automakers use brown for ground.) If the wire is hot, then the bulb is good. If not then replace the bulb before you continue.
Now by looking at the wiring diagram we see that this black wire goes to ground. Skin a little insulation off and connect a jumper wire from there to a good ground. If the brake light lights, then you have a bad ground. Repair the ground wire. Now you have tested the whole brake light system.
This is a simple circuit to troubleshoot, but the troubleshooting technique is applicable to any circuit. A circuit may branch off here and there, but if you look at each section and test it as you go along, you will find the problem fairly quickly and easily.
Please do accept the solution and revert for further assistance.
Posted on May 30, 2009
Hi I am Vortash it sounds like what you have is a bad earth this causes surges of voltage in the bulbs and blows them , check the earth lead on your battery ( usually negative fastened to earth ) and any and all earth connections this usually cures blowing bulbs , if it don't then check the output from your alternator at high revs the rectifier may be breaking down .. hope this helps regards Vortash
Posted on May 30, 2009
A short in the brake light circuit.check out all the bulbs 1 by 1 are they working by getting it tested.if all the bulbs are working then its a fuse or switch problem in the car.but if the bulbs are blown out again then its a short circuit in brake light wirings the wires shoud be checked to clear this short.
to Trouble shoot electical system brake light break light when bulb is good on a 2004 Jeep Grand Cherokee
1)Check socket for power/ground corrosion
2)Check stop light switch for power on one side
3)Check fuse -------------------------
the location of brake light switch is just above the brake pedal under the dash. and the location of fuse is under the dash in the fuse box. The number for the brake light fuse is listed on the inside of the fuse box cover that is located under the dash on the left side of the driver's side on the interior. also check the passenger side fuse panel....fuse number #2 . this will help you, thanks.please do rate the solution.thank you for using fixya.keep updated.
Posted on May 30, 2009
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Posted on Jan 02, 2017
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