Power locks do not work at all
 

I have a friend with problem with a Blazer whose power door locks do not work. The rear hatch button also does not operate. I have checked the PWR LKS 15A fuse, and it contains battery voltage at both ends. I spent time examining the door lock schematic, but have not checked the MIR/LKS 5A fuse in the underhood fuse block yet.

My friend previously had the driver door lock switches replaced about three times, and he also had a locksmith successfully operate the power door locks with a computer, presumably by activating the body control module tests.

Is the MIR/LKS 5A fuse fuse likely to be the problem?

Does anyone have access to the resources (attachments) listed in this screenshot? (Post #6 of this thread)

The vehicle model year is 2001.

Is the key fob unresponsive for door lock/unlock?

Are both drivers side and passenger side lock/unlock switches unresponsive (both ways)?

Is the dash lift gate button unresponsive for gate unlock?

So lock unlock can be forced with a bidirectional ODBII scanner?


There are three fuses involved:

Mir/lck, fuse 7, 3a, UH fuse block
PWR LKS, fuse 14, 15a, IP fuse block
TRC fuse, 10A, UH fuse block

The main ground for all of this is G202, left side of dash. There is also G117, right rear of engine but that’s only for the key fob function.

There are also all of the relays, motors, connectors, wiring and splice packs as well as the BCM involved.

Lets start with the questions at the top and the fuses and go from there.

Edit: Based on your description so far, yes the mir/lck fuse might be your problem as it provides the power to the door switches and lift gate button.


George

Check the 3A fuse and I'll bet that will solve the problem.

Planning to visit my friend next week to work on the vehicle. I will check the fuse first, and if nothing happens, I will proceed to answer the questions.