BCM replacement
 

I have a 09 panel with a problem with the blower fan not starting intermittently. (see https://www.chevyhhr.net/forums/prob...ost827917)(and #post831924)

I have the new BCM. I have gotten both answers to this

Does the BCM need to be programmed? if needed

Does the programming need to be with the BCM installed or can it be programmed outside of the car (not installed)

Is the car needed to program the BCM if it can be not installed.

What do you think the BCM has to do with the fan? Why do you think a computer would forget how to do 1 of 3,000 functions?

The BCM only controls the relay, that you said works. And that is only to make sure the fan is running if the A/C is on.


https://cimg0.ibsrv.net/gimg/www.che...9642cdd5c3.png

Don
I do not know if the relay is working, let.

With the fan not working I have probed the plug at the fan fore and aft and at #4 fuse.
I have a circuit at the fuse and no circuit at the fan so my open is between the #4 fuse and the fan motor. Don’t know if the relay contacts are the open or it might be on the coil side of the relay and I have a logic side problem. Will not know that until I get to the BCM and probe it. I do not know at this time if the coil of the relay is being energized. I have not gotten to the bcm in the car let. I do have a new BCM on hand if I need it.

Take a look at the schematic I provided. The #4 fuse involved is on the underhood box, it also feeds some other things.

Yoy are using some terminology that I am not familiar with; I am not sure what "have a circuit means".

Your problem is most likely in the resistor or the switch or the motor. There is a splice in the Hot wire that somebody found was bad. The BCM has nothing to do with your description of the problem, and you are testing the wrong things.

Computers do not just up and break their software in one application. There are cheaper non-destructive ways to test relays.

Feel free to play Mr. Wizard, but he was analog.

So this post




Did you ever replace the control module behind the waterfall below the radio?

I found this, doesn't look like the bcm is behind the waterfall, looks like it is under the kick panel on the right side of the center console.

http://repairguide.autozone.com/znet...3f807cb09d.gif

That may make it easy to get at??????

I give up, again! You win!

The control panel for the HVAC


https://cimg4.ibsrv.net/gimg/www.che...d5a1f73adf.jpg


Is most likely the problem.

https://cimg3.ibsrv.net/gimg/www.che...6b540b4f07.jpg

With the fan not working I have probed the plug at the fan fore and aft the fan and aft #4 fuse at the blue marks.

I have a circuit aft the fuse this tells me that I have continuity and a complete circuit through the fuse to the battery and no circuit at the fan connector B, so my open is between the two blue dots(#4 fuse and the fan motor). When I probed the fan at connector A&B. I was factoring out the rest of the circuit, the resistor and the HVAC control panel. My open in the circuit is between my two probed test points at the b connector of the fan up through my test point c2/f6 aft the fuse. Do you understand what I am saying?

Ever hear the phrase "start simple?" If something was wrong with the BCM itself, you'd have more troubles than just an intermittent starting blower motor.