Alternator Question

Stephen,

This is about average on my Ford F-250 diesel. Now having said that, my brothers diesel seems to recover a lot quicker than mine, but I know mine is good as far as the charging system, belt, batteries, etc...

How long have you had the truck? If it recovered quicker before and only started taking longer recently, you may want to check all the connections, clean the battery terminals, check the belt for play, but as long as it recovers and starts charging I wouldn't worry too much.

I've had the truck about a year and a half. It does seem to take longer to recover when it's cold and been sitting for a while. Everything is mechanically sound as far as belts, connections, etc. I imagine I'll just keep an eye on it. Thanks! Stephen

The only other thing that might be causing this, is the glow plug relay... it's fairly common for those to go bad after a few years of service... might want to get that checked out.

Dzlman

I recently had my 2007 Chevy Silverado Classic w/Duramax in for the same concern. It was explained as: starting with model year 2005 A new Regulated Voltage Control ( RVC ) system was incorporated. It reduces voltage to 12.6-13.1 volts when in the fuel economy mode. Volt Gauge will fluctuate from 12-14 volts. I have experienced time frames of up to 5 minutes with indicated voltage as low as 11.5 volts; than it jumps to 14.8 volts and stays there. This occurs even at night-time w/headlights/wipers and blower/defroster on. Document ID: 2000522

2007 GMC w/5.3 about 2k miles. About 1 week ago, hit the starter, not a sound. Checked the battery voltage it was about 11.0 volts. Connected my Bat charger for about 15 minutes, fired right up. Voltage now was about 14.3 Immediately took it to the dealer, he load tested the battery 3 different times all passed, the charging ckt also passed. Noted the dash voltmeter was on the high side of 14 volts on the way home. Next day trip, dash voltmeter was just above the "mark" between 9-14 (11.5 volts???) for about an hour of driving and then went right ot the high 14 volt mark. This "RVC" module behavier seems different, the dealer said my truck was recalled, while in his lot before I bought it @ 8 miles to re-program some items to do with the RVC. Also, once the RVC senses a low voltage (whatever that limit is??) it will not even engage the starter circuit, like my problem. Headlights dash etc were lit, but starter ....nothing. I just know it will happen again to me, the dealer said if it does, do not jump it or charge it, but call onstar and have it towed to them for troubleshooting in the failed condition.