Door Lock Problem

[Mike McCloskey]

I have a 99 tahoe two door for which I replaced the passenger side door lock module as well as the entire window regulator. Before replacement, the door lock signal worked fine. Now, after replacement, both door locks only work from the key fob, not the interior door lock switch. Any ideas on why this might be? Thanks!

 

[east302]

Both door lock switches don’t work? How about the one in the cargo area?

The keyless entry signal comes in downstream of the lock switches but the keyless module gets power from the same circuit through splice S256. So if only one door switch is inoperative, see if its connector is disconnected or getting power. That would be C209 for driver, C213 for passenger.

If neither switch works and neither are getting voltage at their connectors, then it seems like there would be a break between those connectors and splice S256 (since the module is getting power). Unfortunately, I cannot find a diagram that shows its location.

 

[Mike McCloskey]

Thanks so much for your reply. Yes, all three locks (drivers, passenger and cargo) are behaving the same - non operable via the interior door lock switches. I should note that all worked fine (except the passenger door lock which was weak and why I replaced it) before I replaced the passenger door lock and window regulator. I wonder if, in the process of messing with the wiring harness in the door during the job I might have done something to cause this. I'll have to study the images you posted.

 

[east302]

It looks like the door control module in that diagram is just for locking cargo doors (not keyless entry like I’d thought earlier). To test, open the cargo doors, lock with the remote and then close the doors. They should then lock, but that module gets power from the door lock switch circuit so that function may not be working, either.

Since all three lock switches aren’t working, the problem should be between splice S256 and up to the convenience center and fuse block.

Check if connector C210 is still plugged into the convenience center (diagram in my earlier post) and if cigarette lighter fuse (#13) is blown.

 

[Mike McCloskey]

Okay, so I'm slightly embarrassed. It was the fuse. All good now! Thanks for much for you're great help!