01trailerpuller

I was driving along today when I got a check gauges light in my 06. The voltage was low so being 7 years old and 100k+ I figured that the alternator had finally gone out. So I pulled into a autozone that had one in stock opened the hood to find the passenger battery had blown the top off the water. Battery acid was everywhere. I replaced the battery and fired it up again. the new battery started spitting acid out the top. Got out a volt meter and found out the alternator was pushing 20v into the battery. So I pulled the alternator. Had it checked was told that the alternator was functioning perfectly. Put it back on and now it was showing 22v going into the battery. So I pulled it again. Same results alternator functioning normally. All the while the voltage in the cab is still showing at 10v. Called Dodge gave them my symptoms. Was told that the ECM is more than likely the problem and the only way to fix it is to replace it. $1800 for the unit and 2 hours of labor to fix it. I don't have $2000 plus at the moment and this is my only vehicle. Is there any way to fix it ASAP. I have to work on Sunday night. ALSO is there anything other than the ECM or the alternator that would cause this?

j_martin

First of all, the alternator wouldn't cause this. When an alternator fails, it fails to put out anything.

The ECM controls the field circuit of the alternator, which is like a throttle for an engine.

For now, disconnect the field wires from the alternator. That will effectively kill it. (temporarily) You will be running on the batteries, but it'll get you home.

Someone with diagrams and knowledge can get to the bottom of the problem. I would suspect the verdict will be ECM. It could, however, be as simple as a wire shorted to ground. Other electronics may also have succumbed to the over voltage condition.

Sorry for ya, not fun.

jtamulonis

you can wire in the early ( 89 to 94) external voltage regulator, and by-pass the voltage regulator in the ECM. take both field wires off the alternator and tape`em seperately so they can`t go to each other or ground. mount the new regulator to the fender and run a 16 ga wire from one mounting bolt to the alt ground stud on the alt housing. get a regulator plug pig-tail and run a switched 12v wire to the top wire on the plug and to either field connection on the alt. run another wire from the lower right pig-tail on the regulator to the other field post on the alt. done. if you want, check the wire diagram for the early voltage regulator, but that`s how my 69 yr old brain remembers how to do it.

01trailerpuller

So I took it to the dealer and asked to talk to the mechanic before they touched it. The mechanic said he had one in last week with the same issue. Apparently the ECM controls the power flow off the readings from the drives side. If there us any kind of low voltage going to the divers side it cranks the voltage till it receives the right amount of power. So he changed the ends on all the battery cables. $150 later it it's running perfectly. THANK YOU FOR YOUR HELP!

NE frmhnd

Yeah, it's kind of a stupid set-up, if you ask me. The grounds should be tied together as well as the hot leads so that this is less likely to happen. If your left battery goes bad, you have to switch your right battery into its place to get home.

Hvytrkmech

If you need one battery you need 2! While connections are most definitely culprits in drivabilit concerns, usually one bad battery denotes another bad battery.

01trailerpuller

Yep one bad battery will kill the good one. I already swapped in the two new batteries put into my 01 in March. It is just sitting so no big whoop.

jmlcolorado

I had the EXACT same thing happen to me! Same cure as well. I happened to have an Air dog bolted to the frame right under the drivers seat so I hear that thing start SCREAMING!
I was really afraid that the spike in voltage would cause damage to other components, mainly the ECM, or cabin computer, but all seems good.

For the 03's, the battery cable had stopped being produced, so I ended up making my own. Still no word on when I can get a factory replacement!

Make sure you keep your cables clean and free of corrosion. That's a start to preventing this problem.