Have a 2006 trailblazer purchased recently and purchased couple key fobs for power locks. suv came with one but was cutting out and figured the battery must be ****ting the bed.

Did the relearn procedure with no success....

lock unlock on door flip key switch twice and doors click click to enter learn mode... 4 seconds later the doors click click again on their own telling me there is a problem? Appears that something on the car end is not working properly. The vehicle does have an aftermarket car starter installed that works fine. I tried changing the battery in the original fob but will not work or learn to vehicle.

There must be a transmitter receiver in the car not working??

Anyone know what I should be testing next and how to test it with a multimeter or what part I should try changing

any ideas?

 

I went through the same thing, then other things started happening rear wiper stopped working, tailgate glass wouldnt unlock, and dome lights are staying on. Come to find out there is no communication with the lift gate module. That needs to be working to program key fobs, or for your key fobs to work.

 

Probably broken wire in the rear hatch which is where the LGM is located .Check for broken wires under the rubber boot on the rear liftgate hinge on top.