pipefitter

I'm driving a '96 with 102,000 miles. I know the alternator has never been changed. This afternoon I while driving home, (about 45 degrees and a steady rain falling), the "GEN" light popped on. The voltmeter was showing discharge, but not all the way to the red line. This sounds like a bad alternator to me, but I'm open to suggestions. My question is where is the best place to buy an alternator, or should I have mine rebuilt? I don't really trust re-mans from Auto Zone, Advance, etc. Thanks in advance for any ideas!

pipefitter

I checked all the battery connections, and cleaned them. I also looked at the alternator fuse under the hood, and it looked good. No change on the voltmeter, but the GEN light didn't pop on,(but I didn't drive it anywhere). I'm assuming it's the alternator, but a little concerned about who to buy from.

patdaly

Could be, but be advised, when I have run thru significant snow, mine will pop on from time to time. When my Alt. died, it popped on and stayed on........

102K is a bit early for one to go, but not out of the question, I think mine made it about 160K..... I would probably drive it for a couple of days and see if it stays off, unless you have a trip coming up, then I can guarantee you it will die at the furthest possible point from spare parts.

I just got a lifetime new unit from NAPA, but if you have a good local rebuilder, I would probably go there first.

If you are in a pinch, they used the same alternator on several Dodge products around the same timeframe, you just have to change your 8 rib pulley to the new Alternator.

pipefitter

Thanks. Like I said, there was a steady rain coming down, but I hadn't gone through any standing water, and the belt is only about 5 months old. Once the light came on, it didn't go out on a drive of about 20 minutes and the voltmeter stayed on the low side. I thought once the grid heaters went off it would get back to charging, but it never came up much. I have removed the alternator and it sounds fine, (no bearing noise, etc). There is a re-builder close by I intend to call tomorrow. Many thanks for the advice.

patdaly

The really screwy thing is when mine pulls that, the light won't go out nor will it charge until you physically shut off the truck and re-start.

I dunno why, but it has done it probably 3 times now........ But mine is only during big snow events, has never done it during rain.

When my light was on, it definitely was not because of belt slippage, something had the charging control circuit confused.

pipefitter

I dropped it off at the re-builder this morning. After testing it, he said I had a burned out rectifier which is odd, but not unheard of. Costs 58.00 for him to re-build it. Sounded like a deal to me.

patdaly

Yep, 58 bucks is about as good as it gets!

Glad you figured it out.

pipefitter

I was wondering about the voltage regulator. The re-builder said he thought it was wired into the computer. If so, I would hate to replace it. Do they go bad?

TxDiesel007

voltage internal regulators do go bad..

my old 96 needed a new PCM because of it.. started overcharging, and an external regulator just turned out to be wishy washy.. I bought a new PCM, and 600 bucks later, and an hour at the dealer.. my problem was solved

patdaly

Yep, voltage regulation is via. the PCM.

Rare to go bad though, does happen, but rare.

pipefitter

Thanks TX and Pat. I really hope the Voltage regulator doesn't crap out on me. Just my luck......my 4x4 Dodge is out of commission because of the alternator, and it snows. (the re-builder didn't get my rectifier ordered in time yesterday), My old Toyota 4x4 is undergoing a much needed facelift, and I can't drive it just yet. My backup is a 2002 6 speed Z-28. There may not be a sorrier vehicle in crappy weather. Thankfully, the snow didn't hang around.

richard.koon

I am having the same issue, but mine will not shift, when you first start it it runs fine and gauge is reading 14v, as soon as you put it in drive and it tries to shift out of first the evil little GEN light comes on and begins to discharge.

patdaly

Sounds like you have a wiring issue......... what year truck are you dealing with and do you have a factory service manual?

richard.koon

no i dont, but i thought it was weird that when the battery is run completely dead and you jump start it, it will charge and run perfectly fine for about 5 min.

patdaly

Could be temperature related pin issue at a connector, man when you start chasing ghosts on trucks this old, i have learned to think nothing is strange, just not seen yet.