My Car: 2000 Mercury Grand Marquis, 81,000 miles. I have had the car for three years. About two months ago I noticed the following: The idle was faultering. Also, when using the turn signals, the digital temperature indicator light would dim and brighten with each flash of the signal. I had the alternator and battery tested. The battery was bad. I replaced the battery. The Idle has returned to normal. However, the temp. indicator light still fluctuates in brightness when the turn signals are on. The mechanic said it was because of normal drain of the amperage
from the battery. Do I have a ground problem? [img]smileys/smiley25.gif[/img]

 

You could check the part # on your alt. and make sure it is the correct one for your car. If the car is loaded and it has a lower amp. alt from a base model I can see this happening. But if the batt. and charging system are in check than I would leave it. But if it really bothers you, check into getting a higher output alt. and or bigger batt. Did this prob occur right before you had the batt. changed and the prob persisted? If so they may have skimped n the battery.