shecom3

Voltage gauge started dropping off to zero and check gauges light started coming on.It would temporarily reset itself back to charge once I turned off and restarted the truck.Took it to a shop to get alt/batt tested and was told the voltage regulator was acting up which is located in the ECM.Just want to know if this sounds like correct info...if so I will start shopping for new ECM.

shecom3

Forgot to mention....truck is 01 auto

volly818

Do a search you can put an external regulator on it.

infidel

Installing an external regulator is easy, cheap and won't effect anything else.
Many people claim that they actually do a better job regulating than the PCM.

Just disconnect the stock wires from the alt, tape them up and wire as below.
Any 12 volt regulator will work. Wires to the alt are interchangeable.

Katmandu

Get your Codes read and report back.

dozer12216

My experience is internal voltage regulator is reliable.
Perhaps take alt off and have tested by friendly parts store. This eliminates the alternator as a variable.
The two wire connector test after reinstall of alt.
One of two wires in small connector at alt is green(?) and feed from relay.
With engine running you should read bat voltage on wire.
The other wire is blue (?) and is ground control for rotor. It will read less than battery voltage of perhaps 8-10 volts or less. If reads batt volts you may have a damaged wire to PCM. It could also be a bad pcm. Spread terminals are frequent cause.

Katmandu

Unless the PCM's internal voltage regulator gets shorted out and damaged by a shorted/BAD CPS (crank positioning sensor).

sawmill

Will this work with my 97? wanting to overcharge not good

RAM2940

If you put a external regulator on, will this fix the check gages light and gage on the dash, or do you ride around listening to the warning bell and dash light on all the time.

Katmandu

I have a PCM out of a 98 that "may" work For Sale for $150.

Check your #s on your PCM and PM me if you're interested.

The # on mine is..... 56040139AC

Check out the chart below...

http://www.aa1car.com/library/2004/c...ailability.pdf

sawmill

Rebuilt the alt last week new brushes and rectifier the gauge steadily rises under high throttle until the light pops on back off the gas it drops light goes out.Last resort is the regulator

infidel

I've only done this mod to 12 valves but assume it would be same on all years.
No lights or bells, think these are a function of the dash cluster rather than the PCM.

Dave Miller

I've got the PCM from my 97 5spd 4x4 3500 that I got from dealer cause I couldn't find one on ebay. Cost $600 sell $350. Used for 5 min test and wasn't my PCM. Replaced the CPS and reused my old PCM. Got install instructions and original MOPAR box it came in.

Maybe the CPS is causing your problem. Cost about $100 for CPS. What other symptoms do you have?