I have an 87 dakota and i have tail lights turn signals and reverse light but no brake lights i have checked everything and still cant fix problem

Sounds like you have a short that is going to ground. You can put a fuse in and have someone watch the rear lamps when you pull the light switch on. You can also check the bulb sockets by removing the bulbs. You could try a 5 amp heavier fuse (be careful only for a few seconds). Check the wiring for a weak spot as well. Try another light switch. I hope this helps.

With a test light check if you have power there with lights on and with lights off, compare left side with right side as far as location in the tail lamp plug for the tail lamp park lights.Trace the harness back to the left side underneath usual corrosion in this area.

The ground wiring on newer vehicles is a little complicated. Older cars, the ground would have been to the body around the tail-lights, but these have a ground wire in the harness and is connected to the turn-signal switch, and other sources. I don't think you have a ground problem. Does the fuse blow as soon as you press it into the fuse-block, or when you step on the brake? I believe you have a dead short somewhere, possibly a pinched turn-signal wire close to the tail-light assembly. Brake lights work through the turn-signal wires from the turn-signal switch on the steering column. That's how you can have one side blinking for turn while the other side stays on for brake. I'm kind of shooting in the dark here because I don't know what all you've done. If you replaced the turn-signal switch in the steering column, you may have pinched a wire or something there. Another thing, if the fuse doesn't blow as soon as you press it in, will both turn-signals work as long as you don't press on the brake? If you can provide a little more information, I might be able to help you more. One last thing....Have you replaced tail-light/turn-signal bulbs? If so, be sure you used the right bulb. You should only have two bulbs, one for back-up lights and one 1157-type combination for tail-lights and turn-signals. I have seen people use a single contact (1056) bulb in place of a 1157, which creates a short from brake/turn-signal back into the tail-light circuit. I do have a 1994 Dodge Dakota.

Did you check socket for power & ground?

Do you have the correct bulb

Check the grounds on your wiring.
If you have a trailer harness, make sure there are no shorts, or crusty connections

Good Luck chasing the gremlins

If both tail lights are not working it is likely to be a fuse or bad connection under the hood or a connector at the back see if you can trace the wires to a connector and see if it is dirlty or corroded.

Check the tail light failure sensor. Located in the driver's side kick panel fuse box. ~Rick89GTS

Check fusebox.

dose it have a trailer package? If so check the plugs that go to the trailer plug that was the problem for my truck to goog luck.

Your turnsignal flasher needs to be replaced with a heavy duty flasher.
also, your boat trailor wiring harness is grounded incorrectly or the harness pig tail is wired incorrectly.
this is why when you excite your tail lights and brake lights that your reverse lights come on and the reason that the lights are dimmimg is because your circuits are looking for the correct ground.