alternator bad?

[redl1nerpm]

Firstly I am new to dsmtuners and dsm's in general. However, Im not new to forums and have already read all the newbie info, and spent the last 6 hours searching for all kinds of stuff. This forum rocks! I just picked up a stock 91 Talon Tsi AWD and its a fun car.

Anyway, 1 problem Im having that I couldnt exactly find by searching is a weird one. Basically when Im driving, the battery will drain quickly, after a short while the lights will be really dim and the car will eventually die from no power. When I shift the brake, battery and I think coolant level (yellowish looks like a radiator symbol) warning lights all light up a bit. At idle they really light up. Im pretty sure my problem is the alternator, but Im also thrown off because theres a lot of lose wiring from the stereo that was once installed in the car. That and the previous owner stated the alternator is fairly new, though maybe he's lying or it was a bad alternator.. My battery is brand new.

So can I test the alternator myself, or do I need to take it off and bring it to autozone (im not driving the car there like this)? I have a digital multimeter, but I am no electronics expert (obviously).

 

[xveganxcowboyx]

Test the voltage on the battery when the car is off. it should read 12V. Start the car and test the voltage off the battery again. It should read 13.8V when running. If it still reads 12V (or less) the alternator is not putting out proper current.

 

[Defiant]

When I shift the brake, battery and I think coolant level (yellowish looks like a radiator symbol) warning lights all light up a bit. At idle they really light up.

Your alternator's dead.

 

[91gsxboosted]

Firstly I am new to dsmtuners and dsm's in general. However, Im not new to forums and have already read all the newbie info, and spent the last 6 hours searching for all kinds of stuff. This forum rocks! I just picked up a stock 91 Talon Tsi AWD and its a fun car.

Anyway, 1 problem Im having that I couldnt exactly find by searching is a weird one. Basically when Im driving, the battery will drain quickly, after a short while the lights will be really dim and the car will eventually die from no power. When I shift the brake, battery and I think coolant level (yellowish looks like a radiator symbol) warning lights all light up a bit. At idle they really light up. Im pretty sure my problem is the alternator, but Im also thrown off because theres a lot of lose wiring from the stereo that was once installed in the car. That and the previous owner stated the alternator is fairly new, though maybe he's lying or it was a bad alternator.. My battery is brand new.

So can I test the alternator myself, or do I need to take it off and bring it to autozone (im not driving the car there like this)? I have a digital multimeter, but I am no electronics expert (obviously).

99% of the time if your driving and the lights dim and then your car dies its the alternator. If the car drives fine but when you park it, then try to start it and it doesn't start, then its the battery.

 

[steve]

Test the voltage on the battery when the car is off. it should read 12V. Start the car and test the voltage off the battery again. It should read 13.8V when running. If it still reads 12V (or less) the alternator is not putting out proper current.

Or the alternator fuse is blown and the alternators output isn't reaching the battery.

Steve

 

[xveganxcowboyx]

Or the alternator fuse is blown and the alternators output isn't reaching the battery.

Steve

Good point.

Or a wire is horribly corroded. Happened to the + on my 944. Had to cut it back 4 feet and replace.

 

[redl1nerpm]

Test the voltage on the battery when the car is off. it should read 12V. Start the car and test the voltage off the battery again. It should read 13.8V when running. If it still reads 12V (or less) the alternator is not putting out proper current.

checked it before and it said 11.8 (was almost dead), then started it and it was at 13.81 or so. I think I had it on the right setting. The car was idling at about 1400-1500 though because it was cold, but the warning lights were still barely on. Ill have to do more testing when its not 30 degrees out side and raining..

 

[ddavisaf]

Uhh buddy. At 30° it's not raining, it's snowing.

 

[redl1nerpm]

Uhh buddy. At 30° it's not raining, it's snowing.

trust me its definetly raining and below 32..

 

[xveganxcowboyx]

Uhh buddy. At 30° it's not raining, it's snowing.

Adn believe it or not, sometimes it snows above freezing