I think I can help you with your lighting problems. The Chevy Venture and the Pontiac Montana are the same van and they share all the same problems that were created by GM's genius engineers. I have replied to other threads in this column about the same problem, so you can look deeper to find a more thorough explanation and fix for it. It might be in the Pontiac Montana column too. Just look for my user name under light problems. I will give you the readers digest version. I am 90 percent sure your problem lies in the wiring bundle that runs across the floorbard in front of the driver and passenger seats. Do your power windows and locks act up sometimes? All of these wires that run the taillights and power options are in this bundle of wires mentioned above. You must remove both front seats and pull back the carpet from the front of the dash to about where the seats were. There you will see a black wiring enclosure. If you cut off all the tape and take the wires out, you will see there are about a dozen or so connections where 2 or more wires come together into a splice joint that is covered by black duct tape. Remove the black duct tape on all of these splice joints and you will see the green ooze known as corrosion. Probably most of the wires fell apart while removing the black duct tape. Try to remember where they go. You will have to fix each one of these one by one. First cut back the infection(corrosion). Strip back the wire until you find good wire. You might have to add some wire. Crimp these together with a new crimp connector and heatshrink the splice joint afterwards unless you want to do it again in 50,000 miles. This should fix all of your wiring issues. Make sure you get all of them. There are a few on the passenger side that run up to the dashboard as well. Get them all and then tape everything back up. What happens is water from snow or rain soaks through the carpet from your shoes, a leaky windshield, or a heater core leak and gets into the wiring. Spilled soda drinks work quite well also. This moisture gets into the tape and then corrodes the wiring because there is just a piece of duct tape protecting the crimp. GM needs to learn how to seal the exposed wiring if they are going to put it directly beneath your feet. This happens on all of their vans. I laugh everytime I see one of these vans go down the road and the back lights blink and light up like a Christmas tree. When they add the blinker, its a real light show. Anyways, I hope this helps you. If you have any more questions, feel free to ask. This is something you can do yourself. If you take it to a garage they will charge you $88 an hour and they will only fix what is corroded, leaving future problems.