Engine/Transmission (1998.5 - 2002) alternator? battery?

[cmills]

A couple weeks ago while out plowing snow I could smell something getting hot, a few minutes later the check gauges light came on and I noticed the voltmeter was going up and down. I figured it was the alternator, so I changed it, seemed to have fixed the problem. Then, this morning while out plowing again the light came on and the gauge done the same thing for a few minutes then it stopped, nothing was getting hot this time. After I got done plowing and was heading home on the highway it seemed that the voltmeter was reading a little higher than normal. I think its normally right about 14, where as today it was a little higher maybe closer to 15.



Any ideas as to what might be wrong?





thanks,

Cory

 

[JLandry]

Cory,



Voltage regulation of the alternator is controlled by the PCM, which is located on the passenger side firewall. It's possible something is wrong with it.



Have you cleaned and tightened the battery terminals and checked that the ground wires connections are clean and secure?



John L.

 

[cmills]

I'm going to go have the batteries tested today around noon and see if there is a problem there, and if not I guess I'll take the alternator off and then and have it tested to make sure it is ok. How do you check the PCM to tell if it is bad, and if it is, how hard is it to change? And the approximate cost.


Thanks for the help
Cory

 

[DavidC]

How about the sensor under the drivers side battery that is in the circuit also. I would have to read up on it since it has been years since I first researched it but remember it is there and also stated the ohm's to test it.



Dave

 

[Skydiver]

Sounds like a positive wire has chaffed and grounding out. Check your plow lights/hardware.
These problems are hard to find, because if the truck is not moving everything appears to be perfect.
I would not use it until I found the problem,,,if you like your truck.

 

[cmills]

I went and had the batteries tested and one came back at 13. 24 volts and 491cca and the other was 13. 41 volts and 320 cca at 16 and 20 degrees Fahrenheit. I know the cca were low but they were both fully charged. It showed the alternator putting out 14. 74 volts NO LOAD and 14. 55 volts LOADED. They said everything was fine other than the cca being too low.



I'm wondering if the gauge was so low this morning because of the fact that it was so cold (-2) that when I started it (the truck had been sitting for around 15-20 min) that the grid heaters were drawing alot of power plus running the plow right away was just too much draw all at once. I never had a problem after the first minute or so. What do you guys think?





Thanks,

Cory

 

[Seane1987]

The grid heater and the plow at the same time will defiantly do it, but you need to have the batteries replaced if the cca's are low. I suggest leaving it on a trickle charger overnight and then load test them.