Is voltage regulator bad?

[Kenneth Cole]

Hi
Ok, with the batteries charged up and the engine running, my volt gage runs in the middle of the yellow. I added leads across the gage, and it is reading around 22 volts. As I drive her the gage will run down to the bottom of the yellow and still read about 22 volts.
Is there a way I can tell if the problem is with the voltage regulator before I spend the money on a new one?

Thanks for the help

Ken

 

[Coug]

What generator do you have in your truck? If it's the 60 amp, a regulator is under $100.
If it's the 200 amp, you can pick up a used regulator in the $300 range usually.

If we don't know what generator/regulator we're trying to troubleshoot, then we can't always give accurate information.

 

[Kenneth Cole]

Hi
My Humvee is a 1991. The generator is a 60 amp , 28 volt Prestolite AMA5104UT.

Ken

 

[Mogman]

You need to check an make sure you have the alternator excited by the PCB look and see that you have the same (22V) at the ign. and the output terminal at the alternator, when running, of course be careful
Check that on the 60A it is the same terminal 5A should be the wire marker, make sure you have battery voltage there first. As Coug said not too expensive to fix

 

[blutow]

Hi
Ok, with the batteries charged up and the engine running, my volt gage runs in the middle of the yellow. I added leads across the gage, and it is reading around 22 volts. As I drive her the gage will run down to the bottom of the yellow and still read about 22 volts.
Is there a way I can tell if the problem is with the voltage regulator before I spend the money on a new one?

Thanks for the help

Ken

Is this new or ongoing issue? Are you sure the multimeter is accurate? 22v is basically a dead battery. I'd run a test on battery voltage as well as voltage on the output on the generator (all while running). All the readings should be really close to what you got at your voltmeter gauge. If not, there are likely wiring issues. If all the same and it's really 22v, the problem is likely in the generator/regulator. If it's a really new issue, you might want to check that your glow plugs are not stuck on. That would cause a big voltage drop, but I assume it would create other problems pretty quick if that was an issue.

 

[papakb]

You can safely read the alternator output voltage on pins W and V of the STE/ICE connector without running leads around the truck.

 

[Mogman]

You can safely read the alternator output voltage on pins W and V of the STE/ICE connector without running leads around the truck.

Well not necessarily, W is ground at the shunt and V is connected to the battery positive at the battery box, has no reality as to what may or may not be happening at the alternator output/exciter terminal with wire marked 5A at the alternator.

 

[Mogman]

Hi
Ok, with the batteries charged up and the engine running, my volt gage runs in the middle of the yellow. I added leads across the gage, and it is reading around 22 volts. As I drive her the gage will run down to the bottom of the yellow and still read about 22 volts.
Is there a way I can tell if the problem is with the voltage regulator before I spend the money on a new one?

Thanks for the help

Ken

Also it does not matter what is at the gauge, that could possibly be its own issue, are you reading 22V across the batteries when the engine is running?

 

[Glider]

You said with batteries charged 22volts? That seems low. As suggested start with the exciter wire, if it has voltage save yourself the trouble and get a 100.00 replacement. You can swap with the alternator still installed. It is a common failure. You can visually inspect the brushes with the regulator removed.

Did you do any work to any other electrical items prior to this?

 

[papakb]

Mogman, Your right that you want to read the voltage as close to the generation point as possible to avoid any losses in the cables and connections but I think measuring the voltage at the STE.ICE connector is a whole lot safer than some of the bubba rigs I've seen with guys trying to measure it with the panel opened up and jury rigged extender wiring. The wiring from the alternator to the starter and batteries is pretty heavy gauge and if the connections are good the losses should be minimal. Those of us that understand electricity know how to do this properly but think back to some of the cluster****s you've seen non-electric guys do in the past. I've seen some rigs so bad I wondered why they hadn't already set themselves on fire! 24 volts is getting up to the point where you might just feel a tingle when you touch the wires and it arcs pretty good if it hits ground.

 

[Tow4]

Put the multimeter leads on the batteries and read the voltage there. If the battery voltage really is 11 volts each, I have a hard time believing it would start.

 

[Kenneth Cole]

Hi everyone
I haven't had time to do all of your ideas witch I will be doing. I did drive into town today, about 25 miles and the gage went into the green for about 20 minutes. But when I stopped and started again it was back into the yellow and stayed there all the way home. When I got home, I read the voltage across the batts with it running and it was at 23 volts.

Ken

 

[Glider]

That symptom still points to a bad regulator.

 

[Kenneth Cole]

Hi
I think your right. I have ordered a new voltage regulator. Will see if that takes care of it.

Thanks all for the help.
Ken