Volt meter issue

15 volts is #### good. I'll take it.

usually the problem goes the other way sinking to 9 volts then all the computer crap quits.

 

Suggestions ~
Bad regulator or
A loose conection or
A bad / cracked wire .
First check that the connections are tight,
Then if you have a multimeter hook it up and with engine running twist / shake / move the wires around while watching the meter and see if the voltage jumps.

 

I chased the same issue on an old pickup of mine for months (wasn't a daily driver, only worked on it when I had some motivation). Voltmeter would randomly peg out at max. Drove around with voltmeter attached to battery and would only read 14.4 at battery. Thought for sure my dash cluster was buggered. Couldn't bring myself to just throw parts at it. One day I had my ohmmeter out and was checking resistance in my battery cables. Everything looked good until I gave the frame ground a wiggle. Boom 80 ohms! Pulled the cable and cut it open. Rotten in the center. It would make contact fine until the engine torqued up when you tromped on it. Basically the moral of the story is start with the basics. 99% of the time its a simple fix. Check and make sure your battery, alternator and starter cables are clean and in good shape. If that's good, get alternator tested. If that checks out, test the voltmeter on the dash (not sure if the Prostar has a true voltmeter or just displays what the computer tells it to).

 

Im guessing that if it is not a analogue volt meter, a old fashioned gauge then the computer tells it what number to show.

The tidbit about rotten cables is a remembering for me. It's great these small things are brought up.

 

I had an issue a few years ago with my volt gauge reading 15+ volts. Turned out one of the + connections in the battery box was touching the battery box cover while bumping down the road. It was a +connector from a breaker for my APU ,not one of the main cables, but it was attached to the main wiring.. Got lucky and found it on my own. Secured wire with zipstraps and no more 15+v.

 

First check the fuses, then check the terminal connection , if they're fine, check the main post solenoid , mines was located on the top right corner inside the battery box. The connection was tight, but when I wiggled the wires, (had the door open to hear any peeps) the dashboard went haywire for a second.
The seloniod connection wires were loose on the inside of the main post seloniod.