thanks for any help you can give.

 

If your speed sensor was bad, your speedo would be flaky as well.

Did you test at the PCM? Or at the trans? If you have power on that wire at the PCM, it's possible the PCM itself is toast.

 

excuse my ignorance but what is the PCM? and where do I locate it on my 2001 dodge ram? I checked it at the connector coming out of the transmission.

 

ok I think I figured out what pcm is. Power-train control module. I think it is located on the passenger side against the firewall. but there are a "million" wires coming of that thing. which one do I test and do I test it like I did the one coming out of the transmission?

 

Should be three connectors on the PCM. (and yes, that's it on the passenger side firewall.) You want the center connector. If you unplug it, the pins are labeled what number they are on the side facing the PCM. (disconnect battery before unplugging it.) See which on it is, (pin 21, brown wire.) Mark it so you know which one it is, plug the connector back in, hook the battery back up, and start the truck, see that you have 12 volts right there at the connector. if you do, PCM is toast, if you don't, trace the wire, and find the break.

 

I have power at center connector, pin 21, brown wire at the PCM. What next? I take it thats the same wire I tested at the transmission? So you're saying that if I have power there the PCM is bad?

 

That's what it looks like.

You could try wiring a switch to ground on that circuit, run the truck up to about 50 MPH, and flip the switch. If O/D engages, PCM is bad.

 

ok. can you explain how do I wire a switch to ground on that circuit? I'm trying to understand all this. The switch is supposed to shut off the power from the brown wire?

 

Nope. The PCM controls the ground side of the circuit, it energizes the O/D solenoid by provided a path to ground on the circuit. All you need to do is splice into that wire, wherever is convenient, run the wire into the cab, hook it to a switch, then another wire from the other pole on the switch, to a good ground.

At 45 MPH or greater, just flip the switch. Trans should shift into O/D very shortly thereafter. If it does, PCM is bad. If it doesn't, solenoid is bad.

 

ok. thank you for your help thus far. Im not that good with electrical so let me see if I understand what you are saying and you tell me where I am wrong.

The brown wire is supposed to not be hot, right? but because it is hot that means the PCM is bad. by hooking up a switch I will be grounding out the brown wire? But if the brown wire is hot and I try to ground it out won't that blow something? Can I just splice into the brown wire at the PCM and run it into the cab and hook another wire to a good ground and just touch the 2 wires together at about 45 or 50 MPH?
sorry to be a pain I'm just trying to understand what Im doing.