I have a 1997 Wrangler. The battery voltmeter in the dash is flaky. When I start the Jeep it displays 14 V. After about 5 minutes of driving the needle quickly nosedives and points to 9 V.
It has done this 3 or 4 times in the past week.
With the needle pointing to 9 V and the engine still running, I measured the voltage at the battery posts using a digital voltmeter - it was 14 V, which meant the alternator was charging the batteries (thank goodness).
So what would make the battery voltmeter in the dash do this? A bad connection somewhere?