I have an intermittent charging issue, one that also renders my cruise inoperable. One would natually suspect the hall effect sensor, but if the field was interupted (like bad brushes) would the computer shut down the cruise and ac compressor also? Just curious. I replaced the alternator a couple of years ago, but it could be that. I just don't know how the computer is programmed....

p.s. where do I get one of those BHA (big honkin alternators)?

 

Sounds like your crank shaft sensor, its right on the front of the motor right above the balancer. Check the wires and make sure there not just unhooked or broken. Its how the ecm knows the motor is running, which tells your alt to charge, cruise to work ,a/c clutch to kick in. The ecm thinks you just left the key on so it says you don't need all of that stuff if you not moving.

 

Wires are good....

 

Mark,

When you say 'intermittent' charging issues, it sounds like a bad ECM. Mine went bad just under 2 years ago. I would be driving along and then all of a sudden... the OD kicks down into 3rd gear, the speedo drops to 'zero', the A/C stops cycling and the voltmeter dropped to 12 from 14. At the time, I called a local auto electrical shop and was told those ECM's were no longer available from the dealer and that a rebuild would cost me at least $400. I searched online and found a Mopar dealer and had one shipped to me for around $227. I've never had those symptoms return after I swapped out the ECM. It took less than 10 minutes to change. I, too, at first checked the crank sensor and all the possible wire connections to make sure those weren't the culprit. Good luck.

Aloha,

 

Here it is - https://www.dieseltruckresource.com/...ght=alternator

 

I've purchased reman ECM's for 1st gens at Auto Zone and Advance Auto Parts. Do check the crank sensor wires where they come up to, and over the top of the block on the front. Mine had a very, very small spot worn bare and would ground out against the block, giving the same symptoms. I had to actually look at the wire because you could not feel the spot with your fingers. A little electrical tape was all it took.

 

The spedo reads fine, and if I cycle the power while driving it sometimes rights itself. Seems to happen only at night with the lights on, and is broght on by acceleration. I still think it's the field coil, but I will visually run the CPS wires just to be sure.

 

The computer uses the crank sensor to know when the engine is running. When there is no signal from the crank sensor, the computer "knows" the engine is stopped.

Check those crank sensor wires carefully, as well as the sensor gap. The ASD relay (front one on the driver's fender) could also be flaky, or just have a flaky connection. Swap it with the A/C (middle) or starter (rear) relay and see if the trouble goes away.

 

I checked the gap with a brass feeler gauge, checked the wired. The relay idea is a good one and I will check that. It did it again tonight, so I just turned the key off and coasted in gear for 5 seconds, turned it back on and it started charging again.

I'll swap it tomorrow with the A/C relay.

 

Yesterday morning the speedo wasn't working, but it WAS charging and the cruise was working. After a while the speedo came back.
Starting to lok like the PCM is getting Alheimers..

 

I still think it's in the wiring, but where?

 

Last night I noticed that when I reved it much past idle it would quit charging, but when it came back down to idle it would charge again.
Brushes?

 

This morning everything was working except for the cruise control. Cycle the power on the freeway and it came back. Can't be the crank sensor because it wouldn't charge and the air wouldn't work along with the cruise. Could be the ECM,...... Bothers me that it is intermittent and changing. Could be multiple problems giving me seemingly conflicting symptoms???????

 

Chicken or Egg?- - - - -EGG{{{{{{ Dinosoaurs laid eggs waaaaaaaayyyyyyy before the chicken was ever thought of!!

 

How do you know the dinosaurs didn't have feathers? And have you ever seen chickens chase (and catch) a mouse? They are like little velasoraptors!