2nd Gen Non-Engine/Transmission Alternator problems?

[SLangegger]

On my 95 truck, the check engine light came on. I noticed the the alt. gage was way down. I got home, shut the truck off, opened the hood, looked for any disconnected/ damaged wires, and restarted. Everything was fine. Since then i have been getting an erratic reading. Sometimes it charges, sometimes it doesn't. I did a few searchs, and was wondering if its the PCM or the alternator? Is there anything else common the happens on these trucks? Im gonna get the alternator tested, but i was wondering if this is a good place to start.



Thanks

Steve

 

[BigPapa]

I've read several posts, had it happen to a couple of friends, and read about it in the mahazine (Issue 50, good article). The majority of the time it turns out to be the crankshaft sensor or connections thereof. On one of my buddy's trucks it turned out to be the PCM. If you have someone with the same yaer model you might try swapping parts.



Scott

 

[nps]

You may want to check your batteries. Unhook them and check the voltage. If one is way down then it needs replaced.

 

[JFaughn]

I had most of the same , the differances were , mines a 94 [ not sure yet , but it may not use the crank sensor on mine ] and it happened once .
What I did was test the alt. this way , disconnect the wiring to the alt. [ mine has 4 eyelet connections , yours may have a plug ] reconnect the large cable , batt. + , reconnect & ground connection , with the 2 left one should have batt. voltage , the other connects to the PCM [ thats where the regulator is ] it should have some resitance , it makes a verying ground connection back to the alt. , these 2 wires are the field in the alt. , the verying grnd. is dependant on the batterys condtion.
I found that when I was testing , that there was no batt. + at field wire to alt. ,
to test the alt. , take the 2 small wires that go to PCM & batt. [ field ] and ground one and batt. + to the other , this will full field the alt. [ max charge ] so not for long becouse running full charge will over heat the alt.
After all that I reconnected every thing and now it works again , till I get in the boonies .
here's a sight that you can get info & parts.
LarryB's Dodge starting problems solved here.

 

[San Felipe Bob]

Alternator Brushes?

My Alternator had 250,000 miles on it.

I had an erratic charging condition as well.

I had it checked on and off the truck.

Each time it passed the test.

After finding out how much a new PCM costs :--)

I decided to personally inspect the Brushes.

They were worn out.

I aquired an Alternator from my local auto parts store.

Problem solved.



I think I had to swap my pulley.



SFB

 

[CumminsPower98]

I would vote to first check the brushes. My cousin's had an intermittent charge for a bit and then died and it was the brushes. I checked mine a while back when it had over 240k on it and they were just about shot so I replaced them with a set from Larry as linked above.

 

[RDelissen]

check your batteries ... I had the same thing going on when they went south. And in the summer it might be less prevalent, but in colder conditions it'll play a bigger role



Plus testing the batteries and alternator first is cheaper than starting to replace stuff at random :-laf

 

[wcjp]

On my 96' the symptoms were the same. Replaced the alternator. No further problems.

 

[J Shocik]

From SLangegger:

i have been getting an erratic reading. Sometimes it charges, sometimes it doesn't.

I had an alternator problem with my '97. At idle, it would show discharge, with a little throttle(1200rpm) it would charge. Replaced alternator and cured problem. Just make sure you replace it with a 136 amp one. The morons at my local Auto Zone tried to sell me a 125.

 

[DieselDoghouse]

When my first alternator went south (brushes) it was also temperature sensitive - poor charging when frigid outside - and not related to the intake heater loads. Apparently the brushes were not making good contact and the rotor wouldn't excite.

 

[San Felipe Bob]

ahh Haaa

That explains the way mine reacted when my brushes went south.



TDR is sooo coool.

Thanks

SFB