Power Features Only Work Or Work Better When Car Is Running


Asked by Oct 28, 2014 at 10:35 PM about the 1991 Pontiac Sunbird 2 Dr LE Convertible

Question type: Maintenance & Repair

I have auto-lock switches and a power roof, however they only seem to work properly when the car is running. The battery is brand new, but I haven't changed the alternator and it may need to be replaced. If it's not the battery, might the alternator be at fault?

Another question on the side, considering there is a locking system in the car, would it be possible to buy a remote to lock/unlock my car from outside?

Lastly, the power windows can be operated when the engine is off, but work a lot better when the engine is running. Is it the same problem as the locks?

I guess my main questions is: Do I need to buy a new alternator? And with the alternator, do I also need to get another new battery?

Thanks to anyone who will help me.

4 Answers


most major auto parts stores can test your alternator. have that done and see what they say. if you are worried about the battery, have it load tested. yes, you can get remote lock systems, but probably not as simple as buying a remote. check with a car toys place or somewhere like it.


I just remembered a few of other things. To begin, here's a little bit more on the power issues: Every time I used the signaling lights, either right or left, the battery and RPM gauges drop when the light is on and come back up when it's off, and it's mostly noticeable when stopped. At times I give it gas, but it accelerates in waves, as if I was gunning it and letting go. It doesn't happen frequently nor constantly. What do you think might be the cause? In order to start it, I almost always have to crank it twice. Would this be related to the weird acceleration? The previous owner didn't take very good care of this old ride, and I didn't get a good look at it until I bought it. Anyhow, I will have the alternator and battery tested, but I'm pretty sure something will need to be done.


Any check engine lights? It would be a good idea to check for stored codes in the computer. Sounds like there could be multiple problems. Your car has an OBD1 system. Just a little better than stone knives and bear skins, but if any of the sensors are whacked out it should tell you. You get the codes by putting a paper clip in the proper terminals in the obd port. Google "how to scan for obd1 engine codes 1991 Pontiac". It involves counting check engine light flashes. Really simple. If you get a code other than 12 you can find it online or get a Chilton or Haynes manual.


Surprisingly enough, no check engine. If something's wrong, my car's oblivious to it. I'll still try to check for codes, though.

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