Blower Motor not working

[chappys4life]

Working on fixing the ac in my 1979 suburban. I just recently picked it up like a week ago. When I got it the ac blew faint but was cold. Now all of a sudden no air output is coming out on ac, vent, or heat.

I figured I do not know the last time any of these parts where touched so did some replacing. So far I have done
- blower motor (gm 15-80213) for a 88 chevy to make it blow better
- blower motor realy ultima ut-rlyu0176
- blower motor switch ac delco 15-71517
- added new 16 gauge ground wire from blower motor to rad support.

Testing I have done
- checked all of the fuses and no blown fuses.
- purple wire from the relay to the fan motor I get no voltage no mater the switch setting.
- If I jump 12v to the new blower it spins fine.
- Old blower motor does not spin with 12v applied.
- Continuity with meter from ground on blower motor & filter to battery

Any suggestions on what else to check? Its driving me nuts

Fuse panel incase im missing any fuses

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[YakkoWarner]

No power on the purple wire means something upstream from there is dead. If all fuses are in fact good, I'd start looking at the blower switch assembly. If the old motor doesn't run with 12V applied, then there is a chance too much current got pulled and did some thermal damage.

 

[chappys4life]

T

No power on the purple wire means something upstream from there is dead. If all fuses are in fact good, I'd start looking at the blower switch assembly. If the old motor doesn't run with 12V applied, then there is a chance too much current got pulled and did some thermal damage.

thank you. I am suspecting the same thing. Just went through the wire harness from the 12v block on the firewall and peeled back the old tape to check all the wires for shorts or cuts. It was all clean. Also cleaned up the factory ground on the firewall just to be safe.

Still have a clean ground from the factory and additional wire. I checked voltage on the plug going into the resistor and not a single lead had any voltage no matter the switch setting. I also went through again and checked the fuses. The only one that was suspicious was the very top 20 amp but still read fine on the meter, instill replaced it. One side looked like it wanted to short it was black.

I have the dash pad off. Thinking I’m going to pull the gauge cluster and start testing. The plugs that go into the control panel what should they be reading? I assume one of the 4 pins on the switch has to be 12v

 

[Edelbrock]

This isn't really the answer you were looking for, but it would be a temporary workaround.

 

[Jgonick]

I checked voltage on the plug going into the resistor and not a single lead had any voltage no matter the switch setting

I believe you should have power on the yellow wire at the resistor (all the time) once the key is turned to run position. That is why the blower runs all the time on the older squares bodies. I would check for power on the yellow & brown wires on the selection switch next. Also the fuse you mention- is very suspicious-That is the one that feeds your A/C- Definitely make sure it has power there and making good contact with the fuse (should be 25 amp).

Attaching wiring diagram in case you need it.