2nd Gen Non-Engine/Transmission Batteries Not charging

[NBean]

After starting in cold weather with batteries partially discharged and the intake heaters cycling. the alternator quit charging and the check gauges came on. I have a service manual and have checked all possibilities (battery sensor, fuses and relays) and have isolated it down to the alternator and/or the Power Distribution Module. My truck is a 1999 24 v auto 3500 with 95K miles. Am thinking about removing the alternator and have it checked. any suggestions? If PDM may be able to buy a used one. would appreciate any comments. Norm Bean

 

[DavidC]

Does your tach work ?. If not it could be your crank position sensor. Could also be a battery problem, ECM, sensor under Drivers side battery (think it is that side, it turns off the charging if battery is to hot) or alternator.

Dave

 

[NBean]

Reply

Does your tach work ?. If not it could be your crank position sensor. Could also be a battery problem, ECM, sensor under Drivers side battery (think it is that side, it turns off the charging if battery is to hot) or alternator.

Dave

Tack works, batteries charged and good, sensor under driver side battery checked and good

 

[JLandry]

NBean,

You can buy a brand new alternator on eBay for under $100, so with that many miles and years on the original, it might not hurt to swap it out to see what happens. Worst case if it turns out nothing is wrong with the original, at least you'll have a spare.

If swapping the alternator doesn't help, then possibly the PCM (Powertrain Control Module) may be faulty. The PCM controls the charging rate of the alternator.

Best regards,

John L.

 

[NBean]

Removed and had alternator tested. It was good. Looks like I have to buy a PCM. New its 875plus tax. Will investigate a used one. Thx all.

 

[Missouri Mule]

Have you checked the volt gauge? Are the other gauges working?

You can put and external voltage regulator on. Do a search for external voltage regulator. It will save you big bucks!

 

[RoosterXP]

check your fuseable link located in the distribution box under the hood, top of the wheel well. I had the exact same issue you did. turned out the fuse was blown. replaced it and presto!
should look something like this: #ad

its where the big red and black wires go into the box.

 

[Bob4x4]

If the fuse is bad you will get 0 output from the alternator..
Were the batteries tested or just charged and assumed good