I was heading back home earlier this week (Tuesday) when the "check gages" light, but no CEL, came on. I noticed the voltmeter was pegged to the right - 20V. Truck running normally, didn't smell or see smoke, and I didn't want to shut it off and it not restart, so I went on until I got home, less than two miles away. Light went off and voltmeter returned to normal reading at the center of the gauge before I got home. It came on again today and the gauge pegged to max as I was headed to the house. Before I arrived, the light went off and the gauge went back to normal (farther away from home this time). I did replace the thermostat Friday (another post) and the light lit before thermo replacement and after, so moving the alternator probably had nothing to do with it.

My (limited) knowledge of electricity guesses that if there is a loose connection, the volts would drop to zero and Truckster would not run properly. Could there be a problem with the gauge cluster?

Or it could be a Halloween thing. Was Joseph Lucas, "The Prince of Darkness," still working for Chrysler in the 'Aughts?

 

When I've experienced this it was charging voltage. I do not, however, have a comprehensive list of everything that triggers the light

 

If the volt gauge was pegged, that is the problem.

What are you driving?

 

Pegged in which direction? I also got it when I failed to remember to connect the primary charge wire after alternator replacement in a '98. I don't remember what the voltmeter read with the wire disconnected

 

Either way. Too high, or too low, the check gauges lite should come on.

Too high runs the risk of boiling the battery..... and that has complications all its own. None of 'em good. Too low, and eventually, the engine will simply stop running, due to a lack of power.

 

When mine did that I had a glazed positive terminal. I popped it off on the side of the road and scraped it clean then put it back on and it's been fine since. This was about 10 years ago when I was still using a battery that liked to breathe all over the terminals.

 

2001 1500 2WD w/ 5.9L, 121k miles. Pegged to max value - all the way to the right. I did replace both battery cable terminals several months ago, cleaned posts and coated with electrical grease. Battery has 9/19 manufacturing date so son-in-law would have replaced it. From previous top end work where I removed it, I suspect the alternator has been replaced because there is a non-OEM sticker with a 800 number on it.

Don't recall if check gages light came on Saturday, won't drive it again until Tuesday.

Had several GM vehicles, internal regulator problems either make light glow faintly or gauge "quivers" IIRC. Alternator rebuilder four miles away.

 

On your dodge, the regulator is in the PCM, not the alternator.... usual failure mode is it STOPS charging though... not overcharges....