my problem is this: my doors lock when i set my alarm, my doors lock when i use my factory keypad, my doors lock when i put it in drive like it supposed to, i just put new lock/unlock switches on from the dealer,(both doors)but i cannot lock the darn doors with the switch's....they unlock but they don't lock......they unlock with the switch just fine but they dont lock... i've even locked the doors without the switcheseven installed in the doors....via the alarm remoteand or factory keypad.....what the hell could be wrong!!!!!!! (2000 chevy venture)

 

Take the switch out and test for a good ground on the 2 black wires.If you don't have a good ground, there are a couple places to check. The right B-Pillar, at the bottom of it under the panel are a few wires that are grounded to the body. Check for cleanliness and tightness. Also check the body harness, in front of the right B-pillar approximately 26cm (10in) from the inflatable restraint sensing and diagnostic module breakout for a splice pack. A bunch of ground wires should come together here inlcuding both lock switches.
second thing to do is to cross over the black wire at the switch with the light blue wire. the doors should lock. then cross the black with the white wire at the switch, the doors should unlock. If this works, then the switch it bad. If it doesn't work, trying jumping the white wire to a known god ground, then do the same with the blue wire. If the locks work when doing this, then you have an open or high resistance in the ground circuit. If it doesn't, check for continuity between the white wire, and the BCM connector C2 pin C6, white wire. Do the same for the blue wire and BCM connector C2 pin C7.
If everything checks out ok you will be looking at a bad BCM

 

Shawnvw, Is there a photo or diagram of what you said in regards to door locks, My passenger and driver sliding doors lock OK, but will not unlock. Thanks

 

I had a similar problem on my wife’s venture. It started with the driver side door switch not locking then the passenger side then they both stopped locking or unlocking. The problem happened to be the wiring connector. It was under the carpet on the passenger side (front seat). The connector had gotten wet and started to corrode. I cleaned everything out and it worked well for a number of years but now the driver side door lock has stopped locking again so I guess it is time to pull the carpet back and clean the connection again.