i am thinking about buying a 04 ram, with no motor or trans, going to put a 12v in, just kinda curious, i know the a/c is controlled by the ecm, what about the guages, and is there a way to get a stand alone controler to run the a/c, getting the compressor to kick off and on is the easy part, making it work with high pressure switch is the hard part, any suggestions and ideas greatly appriciated, going to sell present truck to do this so getting it done kinda quick is a plus

 

the ecm on the cummins is seperate from the vcm or vehicle control module. you should be fine. just need to put in a manual tach and temp gauge.

 

it also controls the alt, and you need to get a cable feed for the gas pedal, the motor mounts are different, you have to rig up the power steering hoses, no cruise, no tach, radiator hoses will need to be made, temp guage will work, oil pressure wont, this is a fact we did this on my 03 it will work but its a pain, will need to rig fuel seliniod cut off

 

04 had manual pedal to tps under hood.

 

yea your right becuase i thought we had to change it on my 03. oops my bad but the rest of its right on the money. we tried to keep everything as close to stock as possible since it was a hotshot truck. we had to use an altenator from a 99 and rig an outside voltage regulator source

 

Not on an 04, ALL the functions run thru the ECU. The gauage module, TIPM, trans control, everything is fed and read from the ECU. You can get the engine to run but doubt any of the gauages or other electrical controls will work correctly.

 

it will work but, i wouldnt try it in an auto. to many things runoff the computers. the 03 we put the 12v in was a stick. like i said it can be done but it aint too cheap about 5k in parts labor. not counting motor or tranny cost since you need a tranny. all i had to do was buy the motor and i found one pretty cheap so thats why i did it

 

I thought TIPM was 06+?

 

The 03 setup is different than an 04. The later trucks have a much more integrated system with major dependencies on the ECU. What you can do with an 03 is not possible with an 04+.

 

well then it will be interesting when i p pump my 07 5.9

 

So did I. Could be wrong though.

 

thanks for all the replys, the truck does have the throttle cable, the motor mounts arent a big deal, what about buying a ecm for an 04(just to run the a/c, alternator,oil pressure, and temp), and building a wiring harness to adapt all the pig tails, my thoughts were to get a 12v, 5spd tranny, and adapt a 04 a/c compressor and alternator on it so the wiring would be the same, i work at a salvage yard so getting a engine tranny t-case and ecm shouldnt be a big deal, makeing it all work like it should from the factory is going to be a task, the speedo is ran off the rear end right, is the oil pressure a two wire plug, and the tach picks up off the tone ring on a common rail, right? again thanks for the replys, by the way the truck is a 1-04 production date

 

the tach runs off crankshaft and cam sensor. i had all the electric boxes and they would still not work the a/c or alt. everything bolts up its the computer reading stuff telling it to turn on and off thats the problem. 03 still had the 5spd and drivetrain so look for that it was the last year for that. went with a mech oil gauge got way better readings.

 

With that production date its an 04.5, even more things run off the ECU. Speedo is run from the ABS on the rear axle, but, the signal is modified by the ECU to tell the cluster controller how to set the gauge. Same as the tach with the CPS. Oil pressure, water temp, essentially everything on the dash is set by the ECU and the cluster controller just interprets.

The big problem is how to not cause ECU shutdown due to lack of injector and IP harness. Could be as simple as ignoring the MIL or things will just get screwy and the truck won't even crank.