My volt gauge is spending quite a bit of time on the low side lately, and it's leaving the headlights a little dim. then it'll bump right up to normal - over 14 for awhile, and it's nice and bright again outside.

is the alternator dying, is there a regulator somewhere? And where's a good place to buy an alternator, should it come to that?

 

Is this right after starting on a crisp fall morning?


phox

 

ah, yea, but i figured that was no big thing.

It's also happening when it's warm, when towing, when not, at idle, just off idle, cruising...all over the place.

 

Its your grid heaters cycling to warm the cold air before it enters the combustion chambers.

 

Except that part.

I'd check all the battery connections and alternator connections,

Pretty sure the regulator is part of the PCM.


phox

 

True enough....after the truck is warm or after you hit 15 mph, the grid heaters should turn off.

Darren, are you sure its doing that when the truck is warm??

 

Yup, the PCM does do the voltage regulation for the alternator. When the regulator circuit takes a dive the PCM must be replaced which, of course is redicuously expensive! The other option is to use a $10 Mopar external regulator and bypass the PCM.....there was a thread a long time ago with excellent instructions on how to bypass the PCM and wire in the regulator.....a search should find it......I'm fairly sure it was in the non-drive train forum.

 

bah! Let's just hope it's the alternator or some loose connections.

it tosses the 'check gauges' light on once in awhile, too.

 

It seems we are back to the bright / dim lights in the morning... If the IAT see temps lower than 65*F (I think it is) then the grid heaters will cycle at start up. This is regardless of engine temp. Once you get to 15-20 MPH then they should shutdown.

You might think about having your batteries checked to see if there aren't getting weak on you. The grid heater takes a lot of juice to heat it up.

 

Oh yea, I should mention that i don't have a working speedometer. Just the brake & ABS lights. It'll work every once in awhile, I think of a ~350 mile trip it logged 26 miles.