1990 M998 voltage problem

[Mack93]

I'm sure this may have been covered before, but while at idle the voltage is fine, right on the mark in the green, but while driving it creeps up in the red and stays there, mine has a 100 amp alt, any thing I should check? Everything seems to be working like it should...

 

[simp5782]

I'm sure this may have been covered before, but while at idle the voltage is fine, right on the mark in the green, but while driving it creeps up in the red and stays there, mine has a 100 amp alt, any thing I should check? Everything seems to be working like it should...

Unplug the gauge and hook a connector to it so you can get it out in the cab and use a meter while driving or hook it to your batteries so see if your voltage is climbing or not to an unsafe level. Could be just a weak gauge. Never trust military gauges. Get a meter and do proper diagnostics to see where to start at.

 

[cucvmule]

Have you checked with a volt meter to see if the charging system is fine?

 

[Mack93]

Yeah I need to pull that gauge, thank you

 

[Mack93]

Yeah everything seems fine..

 

[Mack93]

Ok so I took a drive with the volt meter to the batteries and it is from 29.6 to 30.0 volts going down the highway..

 

[Milcommoguy]

If you believe in your voltmeter, then it is a little high. Read chapter 12 > https://hummerhuren.files.wordpress.com/2013/01/hmmwv_test-diagnostics.pdf

There's more to it, but it's a start, pun intended.

CAMO

 

[Mack93]

If you believe in your voltmeter, then it is a little high. Read chapter 12 > https://hummerhuren.files.wordpress.com/2013/01/hmmwv_test-diagnostics.pdf

There's more to it, but it's a start, pun intended.

CAMO

Yeah my volt meter is good , just can't figure out why it's going to 30 volts driving, it's 24.5 at idle

 

[Katavic918]

Regulator is probably going bad. I was driving down the road and smelled batteries cooking one day. Looked at my gauge and she was pegged red. Ended up putting an alternator in instead.

 

[Mack93]

Regulator is probably going bad. I was driving down the road and smelled batteries cooking one day. Looked at my gauge and she was pegged red. Ended up putting an alternator in instead.

Thanks , any idea on testing the regulator?

 

[Katavic918]

Mine was the 60 amp. I am not familiar with the 100 amp.