Hello, The original problem was the truck wouldn't go into 4wd and there were no lights on the switch. I tested the switch and it tested good with all the correct resistances. I then pulled the module and opened it up and found a lot of corrosion so I replaced it with a used one from a scrap yard which was compatible with my truck. As soon as I plugged it in and started the truck it threw it into 4 low and I cannot seem to get it out. I put the truck into neutral and press 2 hi but nothing happens. I took the encoder motor off to see if that was the problem. Is there certain tests I can do to see if it is working properly ? I took the truck to a dealer because I was told the module had to be progammed. They could not get it to accept a program. They said the module was throwing a C0321 code. What tests and procedures should I follow?Thanks
Last edited: