Volt meter question

[fastcat800]

When I first start my truck (cold) and drive off the volt meter will be exactly on 14 volts at over 1500 rpm. As the truck warms the voltage shown drops from 14 to about 12 volts and at idle the neddle touches the red. When I first bought the truck and saw this I checked the voltage with a volt meter and when the gage read 10 volts at idle I still had over 12v at the battery and over 13 when rpm was increased. Any ideas as to the cause of this? It drives me crazy. I have cleaned the grounds on the battery and where the battery ground cables attach to the engine.

[JohnC]

Sounds like you may have a bad diode or 2 in the rectifier assembly. Funny thing: mine was doing the same thing a few years back, but, before I got around to doing anything about it, it corrected itself. It's been fine now for at least 2 years...

[moondoggie]

Good Day!

You might want to look at my post in How much voltage should alternator put out & where to take reading? (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=008843) (Click in colored text).

Blessings!

[patrick m.]

Being a 94 model, you may want to check all of the connections on the bulkhead. this is the row of studs under the black plastic cover above the right valve cover.
you may have to check the "voltage drop" with a meter to catch it.