Is there a problem with the alternators on the Tib? when I am sitting at a stoplight and put on my brakes my idle goes up and I get more vibration at my steering wheel. When I turn on my rear defroster it gets even worse. I have 30,000 miles on this car and already changed the battery. Still doing the same thing.

 

By the way my mechanic said my alternator was fine but I didn't ask what it was putting out so will ask tomarrow.

 

If your alt.had problems, for eg, excessive output, the MIL or airbag light would come on and have a fault code

 

It does not sound like an Alt problem. It sounds like an electrical problem.

Something is causing the car to work harder to put out extra electricity when you brake/turn on rear defroster.

It could be as simple as a pinched wire grounding out the system slightly and bleeding off electricity.

I would try to check for excessive electricity drains off the battery. With the car 100% off. Put a volt meter on the battery. Then step on the brake pedal. How far does the voltage off the battery drop? if it drops below 12V, then you have a fairly serious electrical problem. The brake lights should not drain that much juice outta the battery.

Also...check for a constant battery drain. Measure the battery's voltage when you first get home. then check it again before you leave in the morning. If the battery lost significant ammount of juice (more than .5V), then you have a constant electrical drain somewhere.

If either turns out to be true, it should be covered under warranty.

 

Random thanks will check it out Thurs. when mech. gets back

 

I don't necessarily have this problem but my car does increase in idle slightly when the brake lights and defroster are on..that is more than one electrical component.

 

Hey, my bad. In orig. post I said my idle went up but it dosen't in fact it drops. I will check for constant battery drain tomarrow. Thanks