My 93 dodge is having charging issues it started a few months ago with the gauge having a barley noticible pulse and the lights would pulse. Now sometimes the gauge is in the middle or towards about 14 volts and some times it is down around 9 volts and will set a code 47 for low voltage. The gauge drops when the lights and heater and everything are on. The lights aren't as bright the windows are slow up and down it acts like it doesn't have enough power. I am wondering what is most likely the culprit the alt, battery or PCM

 

You can check the alternator for field power, (battery voltage when key is on) then ground the other field terminal and it should full field and charge. If it doesn't, then the alternator is bad. If it does, then

PCM isn't supplying the field (ground leg). Could be wiring, or TPS input to the PCM.

There's info in the FAQ section on troubleshooting.

You can either study till you understand it, and diagnose the problem, or you can throw parts at it till it runs. The fastest and least expensive path to a repair is proper diagnostics.

 

I'd start by checking, cleaning and making sure all the battery cables are connected clean, grounds too. Then go to a shop or parts store and have them do a battery load test, (although I have 2 of the big 1100 AMP batteries, I had one that was going south and was pulling the other one down with it, a load test found the problem in 5 minutes.) Then if all is well, and using the matter of elimination and starting cheap and getting more expensive, take off your alternator and have a shop test it as well on their computer bench (usually free) and see if it's putting out full wave rectification DC output att he proper voltage and amperage under load. Then, off to the next item in line, the PCM or TPS (which I have fgound to hardly be an issue on my '03 and my friends '04)

 

the O'Reillys here has a load tester that can check the alt with out removing it from the truck... might be worth calling around you r area for..