2002jeep grand Cherokee brake lights work fine,when turn on headlights,step on brake,lights go out! Help!!

SOURCE: the tail lights are out, so the brake lights-Jeep Grand Cherokee

The park,brake light sockets have a tendency to melt. I would try swapping the turnsignal socket with the brake light socket and see if it works. They just twist out.

SOURCE: 2004 Jeep Grand Cherokee - problem with power windows/locks

This seems to be the affects of a bad dinamo charging your battery . If you take a appart the dinamo you should fine a part called in mechanic terms "the bones" they look like 2 black magnets with a wire coming out of them . They are not expencive and you should not change your dinamo untill you try this first a car dinamo is very expencive .

SOURCE: i have a 1999 jeep grand cherokee and the brake lights wont work

there's a possibility that it might be the socket that the bulb actually goes into. my break light did something similar to that. the socket only cost about 8 bucks from the dealer.

SOURCE: 2001 jeep grand cherokee lights

Solution # 3 worked. Apparently the assembly design in error allows the bulb to be put in backwards which causes the cotacts to be bent down. By rising the contacts in the holder the contact is reestabished. Also insure the bulb is placed in correctly. Thanks for your help!

SOURCE: 1999 jeep grand cherokee - brake lights and turn

The tail lights and the brake/turn lights use the same bulb but, there is 2 filamants in the bulb. One for tail lights and one for brake/turn lights. So just because the brake lights and turn signals work doesn't mean the bulbs are good. If bulbs are good you can check to see if there is power getting to the tail light assy's by unplugging the connector at the assy and using a test light probe the connector (harness side) with the headlights on. If you are getting power to the assy the test light will light. To make sure, turn off the headlights and test light will go off. Hope this is helpful. Good luck.