Intermittent cruise control

[Bunkmuffin]

Hi all... I have a 2003 dodge Ram 2500 with intermittent cruise control.
Does anybody know where the electronic circuits are to control the cruise?
The truck isn't throwing any codes, the switches are ok .I suspect an electronic relay to be the problem.
I don't really want to remove the CPU and send it out for repair if that's not the problem.
Any suggestions please.
thanks.

 

[HemiLonestar]

All controlled by the PCM I'm afraid.

 

[Fast69Mopar]

Hi all... I have a 2003 dodge Ram 2500 with intermittent cruise control.
Does anybody know where the electronic circuits are to control the cruise?
The truck isn't throwing any codes, the switches are ok .I suspect an electronic relay to be the problem.
I don't really want to remove the CPU and send it out for repair if that's not the problem.
Any suggestions please.
thanks.

Without having the VIN to your truck I cant see what options your truck was built with but with a 5.7 truck there is a speed control servo mounted under the battery. If you remove the left inner fender you will see the servo. Check the electrical connector to make sure a previous battery didn't leak all over it and damage the connector or wiring. It looks like your truck has AWAL ABS, or All Wheel Anti-Lock Brakes so the left and right front wheel hubs will have a speed sensor and they can cause problems if the hub bearings have failed or the sensors have failed so there is a few things to inspect. Make sure the hub bearings are tight and the speed sensors are plugged in to their corresponding electrical connectors and are mounted properly to the hubs.

After looking over the wiring diagram for your truck the ABS Module sends the speed sensor signal straight to the PCM. There is also a vehicle speed sensor signal that is sent from the TCM to the PCM.

 

[MikeT]

I had a similar problem with my 06. I could be cruising along and suddenly the cruise control stopped working and we would start slowing down. I sometimes had to go dozens of miles before I could get it to start working again, then it might work to the destination or might quit in a couple of miles or less. Totally intermittent. On my truck it turned out to be the brake switch that was intermittent. Had it replaced and it has been fine for more than a couple of years. Don't know if your vehicle has that switch, but it has to have something to sense you putting the brakes on.

Mike

 

[CVX20]

I had a similar problem with my 06. I could be cruising along and suddenly the cruise control stopped working and we would start slowing down. I sometimes had to go dozens of miles before I could get it to start working again, then it might work to the destination or might quit in a couple of miles or less. Totally intermittent. On my truck it turned out to be the brake switch that was intermittent. Had it replaced and it has been fine for more than a couple of years. Don't know if your vehicle has that switch, but it has to have something to sense you putting the brakes on.

Mike

That's where I would go first.Brake switch may just need adjusting.

 

[Bunkmuffin]

Without having the VIN to your truck I cant see what options your truck was built with but with a 5.7 truck there is a speed control servo mounted under the battery. If you remove the left inner fender you will see the servo. Check the electrical connector to make sure a previous battery didn't leak all over it and damage the connector or wiring. It looks like your truck has AWAL ABS, or All Wheel Anti-Lock Brakes so the left and right front wheel hubs will have a speed sensor and they can cause problems if the hub bearings have failed or the sensors have failed so there is a few things to inspect. Make sure the hub bearings are tight and the speed sensors are plugged in to their corresponding electrical connectors and are mounted properly to the hubs.

After looking over the wiring diagram for your truck the ABS Module sends the speed sensor signal straight to the PCM. There is also a vehicle speed sensor signal that is sent from the TCM to the PCM.

Well here we are almost a year later and my Cruise control issue persists. My VIN is 3D7KA26D53G783673.. I have an electronic cruise and not the vacuum operated variety.
The activation switches on the steering wheel work properly and show continuity when pressed. I tested to see if temperature or humidity affected the operation and that bore no results. I can only assume the problem lies within the ECM and I have no problem removing it for repair but would like to know I'm going in the right direction.
Last year I replaced both front wheel hubs and bearings due to wear. Standard 2 dr cab, 2 WD, long box. Everything came out and went back in very smoothly. The truck had only one previous owner, no damage what-so-ever and lived most of its life in Arizona. Has 150K miles and runs smoothly. Transmission does not have any issues. Vehicle is maintained by me regularly.