Way Outta Control
Join Date: Sep 1999
Location: The Palouse
Thanked 3 Times in 3 Posts
Re: Engine stumbling when blower motor turned on
1. It could be a problem in the 12 volt supply line,
2. Or the ground return.
3. But it is sure that the blower motor circuit,
4. IS causing the ability of the alternator/battery to keep up.
5. Checking grounds don't always do much good.
6. Replacing and refurbishing grounds do.
7. Don't forget to look in often overlooked places,
8. Such as the:[*]Blower Motor Speed Switch[*]Dropping Resistors[*]Wiring Harness connectors[*]Tow halves of the fuse block
9. I still suggest that you NOT use the metal backing of the heater box,
10. To ground that motor.
11. Even if the tub and frame/engine/battery grounds are good,
12. That backplane connected to the firewall,
13. Can become compromised via corrosion.
14. I still favor tack welding a bolt/stud to the blower motor case,
15. And running a heavy, separate ground to it.
16. Then there's not a question that that ground is good.