Volt Meter dropped to 10v Intermittantly

[Keyair]

A couple of times on my trip last week I saw the Volt meter on the dash drop to 10v.
Most of the time it was 12.5 to 14v, and I thought it was maybe just the gauge, but one time when it was getting dark it did it and the headlamps dimmed noticably.
Looking thru the paperwork I see a new Altenator and voltage regulator some time ago...
A short, bad connection or something going bad?
Ideas?

[HowieE]

The first thing I would look at is the battery terminals. Remove them. clean them and retighten them.

If the motor in your truck is a GM, and while the battery terminals are off, remove, clean and retighten the main cable on the starter. GM uses that terminal as the main distribution point and over time an repeated temperature changes the terminal begins to open, often resulting in a no start condition but you may catch it before that happens.

Your problem is an intermittent high resistance most likely caused but a loose connection in the high current circuit coming off the battery.

[Keyair]

Its a BBC, so i will get under there and check. It started and ran perfectly...

[mello mike]

Sounds like an alternator to me.

[345bill]

Another spot to check is where your neg battery cable actually connects to the frame. Mine loosened up there once and caused intermittent no start / volt meter fluctuation.

[Keyair]

I found a bathroom fan that was on, seized, and was eventually blowing the fuses on the main fuseboard.. maybe that was the problem, I will see next time I drive it.

[bkahler]

Originally Posted by Keyair

A couple of times on my trip last week I saw the Volt meter on the dash drop to 10v.
Most of the time it was 12.5 to 14v, and I thought it was maybe just the gauge, but one time when it was getting dark it did it and the headlamps dimmed noticably.
Looking thru the paperwork I see a new Altenator and voltage regulator some time ago...
A short, bad connection or something going bad?
Ideas?

Its probably your ignition switch and/or headlight switch. Several of us have or have had the same problem. On mine the more lights I turn out (parking lights, headlights, running light) the lower the voltage dropped. Also the power feed to the main fuse block is inadequate which also causes problems. There are several threads on these subjects. I don't have time at the moment to go into more detail but if you do a search on my bkahler or guy99 you should come up with something.

Good luck!

Brad