locking problem in 2000 astro

Hi,
I'm new to the forum and am trying to find out other peoples experiences with electrocal/computer problems and the locking system in the Astro 2000.
Symptoms as follows:
All locks suddenly going crazy trying to lock themselves over and over again. Big click, click, click, etc. Sometimes little clicks like it is trying but can't lock or unlock.Than OK for a while [hours or a day or so] than it starts all over again. This can happen sitting in the driveway or driving down the road at HW speed, and anywhere in between. And sometimes it is fine for a few days.
Worst funtional result is that I can not open the back top of the dutch even with the key. Except sometimes if I try and try. And I can never open the lower doors once this starts happening. Always ends up totally non functional. All the doors are effected but can be opened with the key except the back.
Get it fixed with a new locking mechanisim for the rear door. OK for several weeks and than the process repeats. Take it to the Chevy dealer and they fix it [and tell me a story about this happening with a local Funeral home transport car, and none of the mechanics were willing to crawl in beside the corpse and unlock from the inside which is how it can get un-stuck]
Anyway, I am now on round 3 of a problem that has had temporary fixes by replacing the rear locking mechinism [dutch door version] and has now cost me over $400.
{Another problem that started many months ago and is pobably not related is that the fuel gage in the dash and the lighted display indicated range do not work. I can only tell when I need gas by how many gallons have been used.}
Now I have an appointment with the computer car guy who can't tell me what it might cost. He suggested checking the fuses which I will in the morning, but it doesn't make since that it would be so on and off if it were a fuse. One last thing, I think there could be a relationship to this problem cropping up when the weather gets wet.
Anyone have any ideas?
Thanks in advance
Joycesdogs [who get stuck in the back in there crates when this happens, and it's a royal pain getting them out]

We have the same problem. We replaced the lock relay inside the side panel in front of the passenger door near the floor. This worked for a while, but we ended up pulling it and leaving it out. This means you can only lock the front doors and side doors with a key, but the back cannot be locked at all. I believe the problem is a short that is burning up the relay. Our overhead light also blinks on and off at times on a rough road, which also points to a short. Don't you just love those shorts!!