Hey there new member here.

I've got a 2003 GMC Savana 3500 extended passenger van with power door locks. Not sure if it has keyless access bought the van used and never got a fob with it.

Recently the lock button stopped working on all the power lock/unlock buttons on each door. the unlock still works fine and can hear the unlock relays click when pressed. the fuses are okay and I swapped the parking lamp relay for the lock relay and still didn't work. The door lock actuaters still work to lock each door because of the safety feature when driving.

Not sure where to go from here and was looking for some help

thanks,

 

Before I got my '16 last July, I had never heard of a BCM (Body Control Module), but this may be your problem. Here's a link to help. Scroll down to "What a BCM Does".

Bad Body Control Module? Here's How to Tell

And Rock Auto has the AC Delco one for $169.99 (assuming your '03 3500 has a 6.0L V8).

 

Thanks for the response StanVan, I didn't even think about the BCM.

Weird thing the van somehow fixed itself. Went to go do some more troubleshooting this morning and all the locks worked as they were suppose to.
I did some more research last night and might as well post what I found to help others.

the diagnostic steps are from a 05' astro service manual so the procedure should be pretty similar to express/savana