Door Locks Not Working?

My remote door lock/unlock does not work. The remotes are good, I had them checked. What modular controls the door locks? I even reprogrammed the locks and they still do not work.

My door locks will not operate. The relay clicks and the lights flash on the outside and the horn activates, but the doors will not lock. It started when it was a rainy day, and it corrected itself when I turned the front and rear heater on high and let it cook for an 1/2 hour. But after a wet day the problem returned. Now the heat wot help it! I replaced all the relays and pulled apart all the plugs and lubed them w/ switch grease. I checked all the fuses. How much does the Body Control Module play a role in this circuit? I am at wits end. Almost! Please reply.

The key will unlock the door, but when you try any door including the drivers control, all you hear is the relay click. When you push the lock on the key remote, the horn beeps and the lights flash, but no lock.

Thanks I will try this and let you know, can you send me a wiring diagram?

The swith to lock and unlock the doors will not work on the driver or passenger side. The remote will work for the door locks but not the interior switch. Also half of the lighted station numbers on the factory radio are out. I checked the fuses, they're all ok except the 20amp for the transfer case keeps blowing. I'm not quite sure whats the problem.

I have 94 2500 suburban 6.5 TD. The vehical Runs great. Starts right up and batteries are new. When every I hit any accessory other then the radio my guages al drop off, my glow plugs light up, Rear wiper turns on. It almost seems like the unit isnt getting enough power. For example if headlights are on or blower fan is on low, my power window seem to have little to no power to for up and down. Door locks wont work either. If I put my blower on medium or high it dims out and turns off and once off it comes back lit up. Do you suspect a faulty ground to the fuse box or maybe an ECM or ignition Switch. Thanks For you Help.