Door Lock/Unlock Switch Problem

I have a 96 2dr Tahoe LT and since I bought the truck, the interior lock/unlock rocker switches havent worked. Using the remote, the lock/unlock works perfectly. I replaced both driver and passenger side switches hoping that this would fix the problem. Nope, no luck. So knowing that the switches are good, where do I look next? Any common place that I might have a loose wire or bad ground? I dont have a wiring diagram so I dont know where to start.

Well, Power Lock is lt. blue and Power Unlock white and is found in either door boot. The 4 door versions are positive trigger, and the 2 door versions are 5-wire. What that means is if you have a 4dr, those listed wires will show 12v when pressed while the 2dr versions are a little different. They will still show 12v but will also show ground. When one wire is 12v the other is ground. They reverse polarity. Have you tried the switches on the passenger side too? Kinda weird that they work with the keyless and not the switches on the doors

Yeah I have replaced both. I'll get out the fluke later today and test them out. Thanks for the info.