I’m still confused as to why it’s not functioning, but does when directly hooked to battery.

Thank you all

 

so the diesel turbo right.

Did you see the service bulletins?
https://charm.li/Chevy%20Truck/2008/...e%20Bulletins/


I went to Diagrams > Electrical diagrams > Heating and Air Conditioning
and then there's a choice for Automatic or Manual controls , but I don't know what you have.

There's also a diagnostic flowchart for blower motor malfunction ...
https://charm.li/Chevy%20Truck/2008/...20Malfunction/

 

I did read the bulletin before, without really understanding.

it appears engine is a 6.6L V8 OHV 32V turbo diesel.
on the truck it says duramax.

The air controls are digital, not manual (very first pic i shared), temperature goes up and down, speed goes up and down, just no air at all.

from that bulletin, am i to understand that even though blowing motor is functional when hooked up on its own directly to a 12v battery, it will not or no longer function inside the truck?
and that i need to use the new one (new specs).

i will check on the second link that was provided by mountainmanjoe.

research a little more, try to understand more, and post update.

thank you

 

Assuming it was working normally before you took it apart??

 

well, like i said, i think it was working when i tried and purchased it,
but after i changed the speakers, my brother who helped me brought it to my attention that there was no air flowing at all.

I’ll go get a new blowing motor, with the new specs from service bulletin and see if that solves the problem.

i did buy a new one but off amazon so i don’t think it had the new spec ( extra filter whatever)

 

They don't provide a lot of info.
it sounds like moisture (perhaps from the cowl) was causing the blower motors to fail.



My bad. Diagram posted below.




I've had bad luck with parts from Amazon. Especially blower motors. There is zero quality control on Amazon. There's a lot of knock-offs and just total trash.
Stuff from local part stores is best. Rockauto.com is good too.

 

So looking at your diagram ...

The blower motor is entirely run by a control module. (probably that black box on the floor in first few pics)

We already know the motor works fine since you tested it, so we can rule that out.

The other inputs to the control module are:

• battery positive (red+black stripedwire) on pin 6 (should light up test light)
• There should be a speed control signal coming from your control panel (gray + black striped wire) on pin 3.
  According to the diagnostic chart I posted: "The HVAC control module provides a variable voltage to the blower motor control module to request the selected blower speed."
  in other words, the higher the voltage on this wire, the the faster the control module will drive the motor. When you press the "up" on the control panel, this voltage should go up at the same time. But this is not a high power circuit so don't try your test light on it. Use the multimeter instead so you don't fry it.
  Step 5 in the flow chart describes how to test this.
• Then of course you have the connections for the motor itself (purple and black wires). The control module sets the speed of the motor by pulsing the ground (black wire) with a varying duty cycle.
  If you hook up your test light on these two pins, the brightness should go up and down with the buttons on the control panel
• The heavy black wire on pin 5 is ground. As I mentioned before, a solid is ground is necessary for everything to work properly. Unplug the connector. Set your meter to resistance range. Put one probe on some bare body metal and the other on the black wire terminal. It should read less than 1 ohm.
• You can do the same for the control panel. Ground there is pin 8 (black + white striped wire)
• If all of this tests OK, then the control module is probably fried.

 

thx for the diagram,
i'll go over that, and the extra info.
it rained today so i took it easy.
will check on those tomorrow and update.

 

greetings all,

little refresh and update.

after changing speakers and dash without unplugging battery, no more air.
used new blowing motor and resistor to test, but still no air.
also bought a hvac blend door actuator but i did not install it yet, i don't think it would have solved the issue.

went over the info that everybody gave and tested again today.
found out something more confusing.

resistor:: 1 black, 1 red, 1 little stripped purple white ( in to resistor)
1 black, 1 purple (out to blowing motor)

if blowing motor is not connected,
when black test lead is hooked to black wire (in) to resistor, red lead measures close to 12v when in contact with all the other wires (red in resistor, black out to motor, purple out to motor, stripped wire)

but when blowing motor is connected, there is no voltage going to the motor anymore.

i am so confused.

also, i hooked up a diagnostic device to the truck.

not sure if the time is right as i have many things taken off again. (removed dash board again, stereo, trailer control)....

nevertheless, hvac diagnosis shows several faults. not sure if it's related to my issue, but it feels like i have instead opened a big can of worms.

will do more research and update again.