My truck's electrical system has a pulse. It is very noticeable at an idle and goes away at about 1500 rpm. The lights pulse as wellas the voltmeter in the cab. The 97 cummins I had did it a little but this is crazy. Do I need a new or bigger alternator? Thanks.

 

I'm no expert, but mine did the same thing. It simply needed a better ground.
I think this tends to be a dodge thing.

Good luck, Tony

 

What did you ground to?

 

Check the main body ground (on the core support right by the battery).

 

Are you talking about your grid heater cycling?

 

Both my dads trucks do the same thing. You can watch the voltmeter needle sit there and bounce at idle and it goes away when you rev it up.

 

mine did that real bad finally overcharged so bad my battery fried in tucumcari n.m went to johns diesel repair steve a great mec. rewired the sys. relay from alt. to batt. i am no wiring guru but what he did cured my problem. new alt. and batt. it sits where it is supposed to. these people are a
real credit to the repair ind. he called to make sure all was ok going home

 

Mine does the same when I intially start it in the morning, the voltmeter pulsing that is. It did it real bad with this crappy dry cell battery I got with the truck. I've since changed out the battery. I think it's just the heater grid pulling power. The ground on the core support is fine for me, I ain't worried about it though, he still starts up like a champ

 

It's definitely not the grid heater. It does it cold or hot. I'll check that ground on the core support in the morning. Thanks for all the ideas.

 

Thanks, wanna.

 

Well, I checked the core support ground. I moved it to a new spot and cleaned it up real good. No dice- still doing the same thing. I think the alt is just ready to be replaced. She charges fine though. I don't know. Guess I'll leave it for now.

 

I couldn't figure mine out, so I took it to a shop. They ran a small ground from the batt. to the body...fixed the problem. I no longer have a problem with my lights pulsating. The alt. gauge....it still pulsates.

Good luck, Tony

 

Thanks Tony. My biggest issue is my "strobe lights" at night so maybe I can figure it out from there.

 

Next steps: If the regulator is not an OEM Mopar unit, hit the junkyard and find a couple that are (all Mopars from about '72 until the late '80's used the same one) and try them out.

Run a ground from the engine to one of the screws holding the regulator to the firewall.

 

Mine does the same thing. I cleaned up the existing grounds and added more/bigger ones with no luck. That was years ago. So far no problems except that sometimes folks think I'm flashing them .

Back when I was trying to fix the problem someone mentioned that one of the diodes in the alt may be bad. I never got around to checking that. It charges fine. I don't have the external regulator though.