My battery light comes on intermittently when it is/has been raining. Initially we thought it was the battery wires that were loose (they were) so we tightened them up and checked the output from the alternator which was fine. It has happened once since we have done all this (about 2 months ago), any ideas would could be causing it?????

Sheree, October 2009

The fan belt may be loose or worn; when it’s raining, a small amount of moisture may make its way to the belt causing it to slip (warning illuminates). Also, if you are putting extra load on the battery, in rainy condition, such as headlights, ventilation fan, wipers etc, this will make the problem worse.

Rick the Mechanic, October 2009

Is the alternator drive belt tight?

John, October 2009