Hello, I need help with deciding to either replace the PCM on my 01 ram or just adding an external voltage regulator. I’ve read various threads and it seems like the external voltage regulator is obviously cheaper. If I do that will the check engine come on since it’s not getting a signal anymore? Is there a way to splice back in so the cel will go out?

thanks!

 

Why do you want to go this direction? Are you seeing >14.7 volts on the battery with engine on alternator running?

 

Have you gone threw the charging system and confirmed that the pcm (regulator) is the problem?

 

Yes I am. The battery light comes on periodically and the gauge goes to it’s highest point. Then it drops back to normal. Also I keep cleaning the positive battery terminal off and it keeps corroding. I had the alternator tested and it came back fine.

 

There is stuff (technical term..) you can spray on those to shield them from oxygen, and it will at least slow the corrosion.

 

Scientific term, "Battery terminal protector", But you need to clean the terminals before using it!. I would like to see what the terminal looks like under the boot. You should remove both terminals and clean both the battery and the terminals. You cant go by what the trucks gauge reads, They are not always correct. For some reason mine reads low on accession(mainly happens in the summer). Gauge will read around 12 but if you check it with a meter it's around 14.5 where it should be. There are more things to the charging system than just the alternator. A lot of people don't even know there is a battery temp sensor under the battery. Everything needs to be checked out before determining the pcm is the problem.


Also did you check your belt tensioner? They tend to stick and don't put enough tension on the belt causing the alternator to turn slower(not putting out).