2003 Crown Vic x police car

The charging system is over charging 17 t0 18 volts replaced the battery and the Alt. We found out the PCM controls the voltage has anyone had this problem where is the PCM located in the car? The car belongs to my son we don't have any service info to diagnose the problem.

Do a search on autozone.com for your part. Most times they have a repair manual "how to" to go along with the repair. It should give you locations etc.

You need to be sure the alternator is for the 03 only. The alternators are only for that year. The other years will bolt up and hook up, but will not operate properly.

Way2old the replacement is the the 135 amp alt. The thing just jumps back and forth from normal to high volts. I need a pin out chart to check the harness to the PCM they say it controls the regulator in the alt it is really intermittent the battery goes on and off with the voltage spikes. I will try to check the wires under the right front side that looks like a problem area after doing a search.

I'ld be pulling the large + and grnd. cables off,giving them a good cleaning..scrape,brush,grease.. then looking at the smaller connections next.

The 2003 corwn vic police car came with a 200 amp alternator.

pollenjesus is correct. You need the specific alternator for the 2003 CVPI. The 135 amp is for the street version. But here is a diagrsm for you.

http://usera.imagecave.com/way2old/cvcharging.gif

the wires for that alternator go to the computer on the left side with the green wire being the lead for the voltage regulater.I had a simular problem with my 2004 PI and it was a wire short in the harness running along the right wheel well to the front of the car.check for rubbed wires there.