Body Control Module replacement?

99 Venture, last week our automatic door locks quit working, I had it programed to lock once the van was in drive and to unlock once you put it in park. Well once it quit working I replaced the key fob battery, thinking it might be dead. That didn't help at all, checked the programing for the van and it hasn't changed. We bought this van used last summer and the rocker type door locks on the 2 front doors has never worked, we just always use the key fob or the key. I have browsed the forum and believe the BCM is bad now, how hard is this to replace?, I hate to take it to our local chevy dealer, they are high for labor, as most are. Where is the BCM located anyway? My husband is pretty able when it comes to most car repairs. I still need to get a manual for this van, we had one with our Dodge Caravan and it saved us a lot of money in showing him how to repair our van.
Much thanks in advance.
donna

Same thing was wrong with our 98, the push button switch in the door wouldn't work. I cought it on the dealer's lot and they had to carry it to the dealer for BCM re-programming and it worked thereafter.
I bought the GM Factory Service Manual at ebay.

The BCM is behind the left instrument panel insulator. However it probably does not need to be replaced but just reprogrammed. For this you would need a tech 2 tool. The dealer will, of course, have one but a repair shop may have one as well.