So your truck is an obs gmt400 and you should be looking for info up to 1998 not 2000.
1998 chevy silverado door lock fuse.
The diagram posted above does not apply to your truck.
The picture of where the power door lock relay is located is on page 261 of my 92 schematics 92 gm factory electrical diagram manual.
For 1996 chevrolet 1500 the fuse block door access is on the drivers side edge of the instrument panel.
All unlock fuses have no power when i check them with the test light.
If you have a different schematics and it is not on that page look in the table of contents in the front for power door locks then turn to that section in my book starts at page 199 then under the component location heading it should list on what.
There is no power going to any of the locks when i try to unlock them.
Driver door unlock relay in left fuse box.
Gmc sierra mk1 fuse box instrument panel.
These can be used to replace a bad fuse.
If they work then you ve narrowed down your problem.
Door lock relay in left fuse box.
Pull off the cover to cover to access the fuse block.
You may have spare fuses located behind the fuse block access door.
Niether door lock button will operate the locks but the key fobe remote will.
I read right past the c3500 part of your post.
Could the driver side control pod be the problem.
Pull off the cover to access the fuse block.
To remove fuses if you don t have a fuse extractor hold the end of the fuse between your thumb and index finger and pull straight out.
The fuse block access door is on the driver s side edge of the instrument panel.
If they do not then you may have a bigger issue.
Put a test light on the 15 amp lock fuse and press the.
You can remove fuses with a fuse extractor which is mounted to the fuse block access door.
Door lock relay in left fuse box.
Sorry but i m not an installer just an owner trying to find a solution.
Check the position 13 power amp cigarette lighter door lock relay power lumbar seat and a position power door lock six way power seat keyless entry module.
The door lock relay is located under the center of the dash.
Since the door will unlock but won t lock it would seem to be a problem with the gray blk wire at the lock actuator.
15a unlock fuse located in left fuse box.
One of the easiest ways to diagnose the switch is by trying to use other door locks in the car.
When i press any unlock button there is a clicking near in the interior fuse box.
1998 silverado crew cab puthe problem.
If the driver door lock switch doesn t work try the passenger door lock switch or any other door.
1998 silverado door lock.
The only way to get into the truck is using the actual key.