what resistor?
the black box is a control module. There are no resistors in it.

Can you take a photo? There's no purple/white striped wire in the schematic. Which cavity position in the connector is it?

that's normal. Like I said the motor is pulsed.

please follow the steps I posted before

 

In the early stages of my research i learned that it was referred to as blowing motor resistor so i stuck with it.
i can now say that it is the control module.
thx for the correction.

From side of passenger door to control module,
there is black, red, and a smaller wire that is stripped purple and white.

from control module to blowing motor, only black and purple.

i will try the tests again later.

Thank you for the input

 

Thank you.
So it seems your wire colors match the schematics for the 2007 model, not 2008
Anyway, the purple/white striped wire is the speed control signal.
Troubleshooting steps for diagnosing blower motor: https://charm.li/Chevy%20Truck/2007/...-%20Automatic/

 

Thank you, will recheck that at a later time.
i have been trying many different tests and measurements, but need to study the diagram more so i have a better understanding.

again, blowing motor and blowing motor control modules are new.
oh, i did purchase newer blower motor 25973845 but still not working, so i am sure it is not blowing motor or control module,

it has to be further up.

i have been reading that there is a hvac control module too, could that be one of the issue??
i will look into that and update too.

and this is my fuse panel.

thank you all.

 

it's possible
I already explained abovehow you can measure the ground and speed signal on that module.

Per the diagram, 12V is on the red/white wire.
Further diagnostic steps are in the service manual I linked. But you need to rule out the blower module first.
A photo of the fuse panel doesn't tell me anything. Fuses need to be measured.

 

Roger that,
just need a little time to learn and understand as i follow the steps, at least do my part of the job,
thank you all.

 

greetings all,

it took me a little while to update the thread,
trying my best to see this to the end so it could help future readers.

i did research more on the matter.

tried various tests,
still same issue.

recap:
dash board repair and new speakers, then no more ventilation.
blowing motor replaced, blowing motor control module and harness replaced,
no result.

most recent test:
a friend introduced me to "power probe" which is a step above a light tester.

power test at blowing motor control module out to blowing motor: black and purple wires.

without connecting the blowing motor, purple is positive (red light)
black is negative (green light)
i forgot if there was 12 v on purple.

as power probe sends power to the disconnected blowing motor, it functions.

BUT, when blowing motor is connected,
probe at purple and black wires are both red (positive?)

friend tried ( per his explanation on using the power probe) to feed negative through the connector and blower functions.
but overheated the probe, lucky it had a trip fuse.



will try to trace the wires from climate control module to side of passenger door where there is a junction before going down to the blowing motor control module.

i am not familiar with diagnostic devices,
but could it be that simple?
the previous diagnosis that i posted as extra information, it said "hvac control module" in red
could that mean that i might just need to replace the controls on the front panel?

that is what i thought of doing,
but trying everything else before making a purchase as the junkyard quoted me over 120$ for a replacement unit.
what if it does not solve the issue, they don't refund, just exchange or store credit.



will update as soon as i manage to trace the wires

 

hello all,
slowly working on it because it's just a "when needed vehicle"
but still trying to figure it out.

well, update:
i bought a climate control module,
and of course, still not working.

at this point i think i replaced practically all the detachable components of this ventilation system and still not working.

conclusion is that it must be a wiring issue, somewhere.

still researching,

 

Greetings all,
about 6 months later,
update:
miracle, it worked

long story short: make sure to reinstall all the screws as some might be ground bonding screws.

for those who have time to read:
i could not figure out the issue so decided to go to the mechanics.
i stopped by and explained my situation, the mechanic was very helpful, but as soon as i told him that i took out my dash, he would not take my truck in.however he took the time to look up the diagrams for me.

i called another technician who specializes in diagnostics, but he was so busy he never replied back to me when i asked when he could come.

i resigned myself to put everything back together and look for another mechanic.

My oldest brother visited and told me that some bonding screws might be missing, and i told him it should not, but when i reinstalled the dash i remembered that there was indeed a bag of loose screws.

after i reinstalled all of them minus only 2, the ventilation was working again.

i just saved myself an expensive trip to the mechanic.

hope that will help those with the same problem.