my 3rd brake light works on my 2004 pontiac montana but not the rear ones. i replaced bulbs and tail lights work but nothing when you push brake petal

Try your hazard lights a few times. Those switches are common to go bad. That switch will prevent those two brake lights from working. Many times after you use the hazard switch the lights will work properly for a while. Would recommend replacing that switch if this takes care of the problem. Good luck!

The tail lights work and hazards but nothing with the rear brake lights

sounds like it could be a wiring issue. If the third brake light works properly then the brake light switch is ok. Possibly a separate fuse or a common ground. When you replaced the bulbs did they look bad? The bulbs you installed were correct? only reason i ask is a single filament bulb will fit and could make things act crazy. Is this model have the circuit board attached to the housing?

Correct bulbs put in and the old ones looked fine. I think the fuses are under the hood in a box

You can check fuses. Are all the bulbs on eack side set up on a circuit board? One plug for all the lights per side?

Yes all 4 bulbs in one unit attatched with one plug for each side

if all the other lights work on that side the ground should be good. You can check those fuses but those boards are common too. you can check the wires at that plug and see if you get power. I wish i could tell you what color wire but i dont remember.

You may want to try replacing the brake light switch located by the brake pedal, is a common part to fail in many models. Here is a few part numbers: Standard Industries # SLS169, SLS179 AIRTEX / WELLS Part # 1S5214 ACDELCO Part # D7085 http://www.rockauto.com/getimage/getimage.php? imagekey=44606&imageurl=http%3A//www.rockauto.com/info/ SMP/29-SLS169.jpg Happy trails!!