Two trucks that i have been working on lately have the same door lock problem. one is a 2000 the other is a 98.5. The power locks will not work. on the 2000 using the remote you can hear a clicking under the dash but still no locking. The 98.5 remote is and neither one will make a sound using the button on the door. Im pretty sure this is related to the ctm but unsure of the fix. Both trucks have had the cab swaped on them but all original wiring and modules were taken from the old cab and put in the new ones.

Thanks
W Vaughan

 

I may be way off base here, but I thought I would put this out there just in case it might help. Does this truck have rusty doors? I had a similar problem with my truck. It's a 2000 which developed some pretty ugly cancer in the doors (I managed to keep my truck cancer free for 8 out of the 11 yrs I've owned it simply by keeping the salt blasted off of it religiously, however it eventually did catch up with me ). So, anyway, to make a long story boring, Out of the blue I started having the same problem you are. It seems the locks have got a fairly wimpy solenoid to operate them and the slightest drag on them will keep them from operating. Turns out water (or salt) had been splashing up through the rust holes and getting on the solenoids and even the window motors and started to corrode things. I cleaned and lubricated everything with WD and spray lube and worked the locks by hand up and down until they moved easily. then the wimpy solenoid managed to have beer muscles once again!

 

I'm having this same problem... I pulled my switch apart and manually toggled the switch to lock it, and it blew the fuse. Trying to figure out what is causing it to do this.