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.

Why are you testing continuity? You should be looking for 12VDC on both sides of the fuse, then move onto each connection.
Then check for continuity to Ground on the other side of the fan, while it is switched on.

Why not test the relay?

Why not test the fan?

Did you read post #4? "There is a splice in the Hot wire that somebody found was bad"

COMPUTERS DON'T JUST BREAK! Highly unlikely the problem!

I just realized from one of your posts that you are probably looking at the wrong relay and fuse.

There are 2 fuse boxes!

Fuse #4 on the UNDERHOOD fuse box.
Relay #30 on the BCM, which is below the radio on the passenger side of the console/waterfall.

I see relay # 30 for HVAC in that diagram, but not the BCM
See the control switch for the rear defroster, heated seats and so on which are in the HVAC control module, ergo that is were the problem could be hiding.

Look again.

https://cimg5.ibsrv.net/gimg/www.che...02fb9b4eb4.png

Oldblue:
The #30 relay is on the BCM.
Thank you for your help, It’s fixed.

Let me bring you up to speed, I did electronic repair part time for almost two decades, to the component level. I did five years with a very good auto repair shop down here, I was reading Mitchell on demand wiring schematics and directing the techs on what, where to test and where to look. I have fixed 1000’s of wiring problems using Mitchell wiring schematics in those five years. That shop specialized in fixing wiring problems in part because of me.

As I told you the open was between the aft connecter on the #4 fuse and the b connecter on the fan motor leg. Once I found where the BCM was under that kick panel, it was a simple fix. I touched/moved the #30 relay and the problem was fixed, fan came on and has worked every time the car has been started 10-12 times in a row. I have put a very small amount of dielectric grease on the spades of the relay so this problem doesn’t return again.

So, you where just playing with us? You couldn't be bothered to read the printing on the wiring diagrams and schematics or the Owner Manual.

You electrical experts always want to replace computers. I guess you would have claimed that was the fix, since you would have replaced the relay in doing so.

This from Mitchell:

https://cimg3.ibsrv.net/gimg/www.che...fce03350ed.png

So you didn’t check the relay, wiggle it or test it?
Just tested for continuity fore and aft, between the blue dots.

Oldblue:

Please read post #3

I was saying that the open in the circuit that I made with my test probe was between the two blue dots. If you follow the black line between the two dots you will see the relay on the BCM. I also said that I don't know if the open in that circuit that I made with my test probe is in the relay contacts or if it is on the coil side of the relay. There was a outside chance that the open could have been in one of the connectors in the wiring. I did not know where the BCM was hiding in the car.

I put a red circle around the BCM

https://cimg1.ibsrv.net/gimg/www.che...6b6b4fe2be.jpg

did that help?

Well it’s fixed, that’s the main thing , no BCM replacement required just wiggle the relay or if you wish replace it with a known good one.

Oldblue:

Let me step back I seem to be confusing you on what I did. I use a power probe but you can do this with a standard test light. I used my power probe to apply a neg at the connector after the #4 fuse, I had a circuit, the light on the tester would come on.

Then I moved down to the B connector on the fan motor and I did not have a circuit, no light on the tester. This told me that I had a open in that circuit that I had made between connector B and the + battery, I knew from the first probe that I had power going through the fuse so I didn’t have a blown fuse. At that point I know the open was between the two blue dots. The only thing in between the two blue dots was the BCM, relay, some wires and some connector on the wires.

That is why when you said it was in the switches, I knew the switches were after the fan motor outside of the circuit between the two blue dots. Once I found the BCM I was going to probe the for connector of the relay socket. This would have told me that I had a circuit from that connector under the relay to the + battery. I didn’t have to do that, as soon as I grabbed the relay the fan started up. OOOOK! Moved the relay around in the socket and I still had blower fan, problem fixed.

Do you understand all this?

yes I understand circuits and continuity.
What we try to do here is keep it simple.
Blower fan not working, test fuse, test relay, test fan , test grounds and then go into the control panel module.
9 times outta 10 it’s the first 2.
But you wanted to lead off with BCM replacement, the relay is in plain site under the kick panel on the passenger side of the console.


https://cimg5.ibsrv.net/gimg/www.che...ad88423bf5.jpg



https://cimg9.ibsrv.net/gimg/www.che...08938d79e6.jpg

So, let me ask you, why so complicated?

Oldblue:

It was not very complicated, it might have sounded like it was, but it took me about 15 minutes to do the two quick probes and at that time I knew that my open was most likely at the relay or BCM. I don’t have Mitchell on demand any more so I could not use the component locator to find the BCM/relay. The best info that I found was that the BCM was under the radio so I thought I was going to have to pull the waterfall, radio and all that stuff to get to the BCM. I found out that the BCM/relay was under the kick panel back at post #6 yesterday. I have known that it was the BCM/relay for more then a month. See post back on 10/26/2017
https://www.chevyhhr.net/forums/prob...e2/#post831924

If I was still back at Island Tech or Monroe Tire and had Mitchell on demand this fix would have taken me 30 minutes and it would have been done and out the door.

Because of hurricane Irma we do not have a auto parts store anymore so all parts have to be ordered in, that is why I got the new BCM ahead of time. I didn’t need the car down sitting waiting for a part.
US Mail, Fed Ex, UPS is still very spotty and it took a week to get the BCM in here the way it is.

Owner Manuals are available for free through the link in my sig.

So it turns out to be money well wasted, you did not require the BCM , just the Wiggle Wiggle

Yep, but I need the HHR running. The two company trucks are still having problems from Irma. The van still needs a starter and alternator, I have to hit it with a hammer to get it to spin and the pickup is running but it is a HD that only gets 10mpg. We have lost four of the five repair shops on the island. The two shops that I worked for have closed. Had to replace the starter and air pump in the F250 on the ground on my back, like back in my teen years, not fun.

I will see if I can sell this BCM, Its is a new OEM Delphi to recoup my money.