Originally Posted By moretoys
The biggest factor on the PCM is if either one has factory alarm,gray key.
The other issue is they use a bus communication system. (link between all modules)if the modules can't talk to each other, (EG) mismatched vin numbers,systems can /will be disabled. older years wasn't a problem, all you can do is try. Don't remember the exact application for work and no work


I am willing to bet you have a broken/corroded wire. does the engine light come on when the key is rotated on?
a test light and wire schematic will go along way. Do you know if the asd relay is being energized? There is a splice inside the harness between the battery and firewall that gets corroded and results in NO engine light,NO spark, asd relay not powering up, also lose voltage to a certain wire to the PCM. fixed dozens of these trucks for this problem
ignition switch can be problem.


It died about 30 miles from home at a friends place......ran down there today....

with the key on....there is a check engine light and the ASD Relay clicks if I remove/replace it with the key on.....

I assume this indicates the PCM is working ??

If I remove the fuses labeled engine control, I get a "No Bus" instead of an odometer reading, when I install them I get an odometer reading.

I have switched the Crankshaft position sensor and the coil from my other Dodge truck.....

I peeled back the plastic wire covering and could not find anything that looked problematic.....there are 2 bundles of wires coming out of the distribution/fuse block....one bundle t's off and goes inside the cab and to the headlight area....the other bundle runs across the firewall to the PCM.....

Any ideas ?

Thanks in advance