its a 94 1500 ,with 6.5 turbo , lately a night when driving if l ahve every thing on the volt meter drops enough to put engine light on, put the box on to check batteeries all good and while at idle the box says it is charging almost 14 but inside the truck volt meter says just over 12 my buddy says my volt meter inside the truck is tired but l think he is wrong!
because this is my first diesel what do they run at?
thanks Joe

my truck runs at over 14 volts all the time but i made my own 2 gauge main battery wires so that could be why. your saying if you put a multimeter on the batts with the engine running it reads 14+ but the voltmeter on the dash only says 12 or so? sounds like a ground issue. dirty or missing grounds really drive these trucks crazy. i'd say clean up all your ground wires and then see what the meter says.

k that makes scents just started the other night went to clear my winsheid so l turuned fan on high, meter dropped and engine light came on turned fan off and light went out but has been showing weeker every day , and when l put it in gear l get a small dropp in volts so l will check grounds where are all the grounds at?

where are all the grounds at?

Now there's a loaded question :rolleyes:
OK -- First read this http://www.dieselplace.com/forum/showthread.php?t=19063
Follow the links - Fill out your Signature Line and READ the FAQs.
There are grounds all over the place. The above links should help you find most of them. Read, read, read!
Report back once you find that you need more info.

FWIW
This forum is THE BEST source of information I've seen yet on the internet, no matter what the subject.
However; You'll find that these guys are way more inclined to help those who first try to help themselves.:)
Good luck & Have FUN with the truck.

I added two 4 ga. grounds from chassis to block and my voltmeter still reads low - like two ticks below 14 - even though a volt meter on the batteries shows 14.2 while idling. I'm guessing my gauge is crap.....like the rest of the gauges.

The factory guages are not that accurate. As long as you dont have starting issues I would leave it alone. I have not seen anybody posting a fix for the factory volt guage besides replacing them with an aftermarket guage.

l check all my grounds and found one lose so l tightened it we will see if that why the light came on.

Go to a part store like AutoZone, have the batteries tested for free. After you clean all the ground. Also check for corroded cables. The positive cables are prone to corrosion. Pos to Pos cable between 2 batteries, Pos to Alt, Pos to Starter, then also all the ground.

On a 94, you may have to replace some of them now if it has not been replaced before. I have a 95, I replaced all my positive cables except the one to the starter. If you have to replace it, get at least 4 gauge or bigger.

thanks for info l will make sure l check that out ,this is my first diesel but l realy like this truck l knew it was mine when l seen it