Car wont start on 1990 Mercury Grand Marquis

car wont start, hear clicking noise. had battery checked, battery good.Jump start, starts right up. Last night while driving car died completely.

Asked by for the 1990 Mercury Grand Marquis
1 answer
First, fully charge the battery to get a good system voltage baseline. Then have a charging system diagnosis performed. I think you will find that your voltage regulator and/or alternator is underperforming.