The other night my wife and I were driving and the voltage regulator fell completeley out. But my truck still ran. When i got home i killed the truck and when i went to crank it again, it showed the proper voltage and cranked fine.Tonight it fell out again, and we had to get it jump started. after jump starting it cranks right up, but after driving iy falls out again. any solutions?

Here is the whole story..Maybe someone will be able to help. My wife and I went to a roping and had my horse trailer hooked to the truck. It is a 4 door dually with the cummins diesel. The truck ran fine for the 25 minute ride to the arena. After we got in the truck to leave it cranked up with no problem.After travelling about 5 miles the check guages light came on and I noticed that my volt gauge showed it had fallen completely out. the truck still had the same amount of power as usual. I continued to drive it back to the house. I unhooked from the trailer, pulled forward, and killed the truck. When I tried to restart it it cranked right up and the check guages light went out and the voltage guage registered normal. I drove the truck the next dayabout 10 minutes away, and back. No problems. We went to a horse sale last night that was about an hour away. It ran fine no probems, no alarms. When we got in to leave the truck was dead and had to be jump started. Once started the gauges all read fine. After travelling about 10 miles the check gauges light came on and the voltage guage fell out again. After still driving for about 10 more miles I started losing power and then the abs light and brake light came on, followed by the fuel light and the fuel guage dropping. Finally the truck died. It is not a slow drain. It takes it less than a second to go from 13 volts down to less than 8.i hooked cables up to the truck and for some reason, and i dont know it the other side of the cables touched, the voltage guage jumped back up and was fine. I hadn't even hooked the other side to another battery. We travelled again a few miles and the process just repeated itself. I tried hooking the cables up again and crossing them for a sec, but that didnt do it. After jumping the truck off again, it will run for 15 minutes or so till it starts losing power. Any ideas what this could be?

Dear jcb,

I don't know if this helps you, but I'd check the pre-heater. They drain a lot of power.

I have a 2000 Dodge/Cummins and in cold weather when I first start the truck after waiting for the "wait to start" light to go out the truck fires and starts and the voltage drops from 14 plus to 8.

Watching the gauge and listening to the pre-heater cycle on and off I can see and hear the pre-heater draining the electrical power. I hear the little "pop" when the pre-heater starts and I can see the results on the gauge.

Regards,
Goobs