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[gooby]

Hi guys, new member, trying to repair an 03 1500 w 5.7 for someone. Some systems work from time to time like radio door locks etc. Check engine light is on however when I tried to have the codes read the reader never detected that it was plugged into a vehicle. owner claims that the truck was jumped one time with the donor battery hooked up backwards and all the electrical problems started then. Truck sounds like it runs okay and the instrument cluster and transmission work fine but I'm leaning toward ecu problems. Truck starts to run hot when idling but cools down when driving. Never dealt with computer problems before and my question is where is the ECU located and can the dealership test it if I take it in to a dealership. Have most of the lower dash disassembled and am looking for burnt connectors and/or wires. Also is there a fuse block or relays inside the cab i might need to look for? Help me ram guru's. have checked all fuses and relays in the engine bay fuse block. going to flush the radiator today and make sure fan thermos are working properly.

 

[MegaMouseGW]

Most likely you are right. The ECU is going out from being hooked up backwards when it was jumped. Take it out and have it checked at the dealership if they have the equipment.

 

[Redtruck-VA]

Hi guys, new member, trying to repair an 03 1500 w 5.7 for someone. Some systems work from time to time like radio door locks etc. Check engine light is on however when I tried to have the codes read the reader never detected that it was plugged into a vehicle. owner claims that the truck was jumped one time with the donor battery hooked up backwards and all the electrical problems started then. Truck sounds like it runs okay and the instrument cluster and transmission work fine but I'm leaning toward ecu problems. Truck starts to run hot when idling but cools down when driving. Never dealt with computer problems before and my question is where is the ECU located and can the dealership test it if I take it in to a dealership. Have most of the lower dash disassembled and am looking for burnt connectors and/or wires. Also is there a fuse block or relays inside the cab i might need to look for? Help me ram guru's. have checked all fuses and relays in the engine bay fuse block. going to flush the radiator today and make sure fan thermos are working properly.

Where are you located? I have a spare 03 PCM that I might consider letting you try. The over heating problem at idle can be associated with a bad fan clutch. I would check all the grounds for damage. And run a new ground from the PCM to the Throttle Body to the fender ground that the battery uses. I also used one of the valve cover bolts for an engine ground. If you haven't figured it out "Grounds" can be an issue. The Fuse box (IPM) can be easily un-mounted and flipped over to inspect. Good luck...