Not sure exactly what is going on, but suspect a fan motor in the process of failing.
Successful resolution steps:
1. Checked Black/Orange wire at resistor for voltage and found it to
2. Checked Black/Orange wire at fan motor for voltage and found it to
3. Fan was not running, so I removed it.
4. Plastic squirrel cage was filthy so I cleaned it off. Motor was dirty so
I cleaned off the outside and blew through the holes in the case by
mouth. Some black dirt fell out.
5. Rotated motor shaft by hand. Motor turned freely, but there seemed
to be more resistance than I expected. You could turn it, but not
6. Hooked motor back up to connector without squirrel cage to see if
it was running (motor out of heater housing). Motor appeared to be
running fine. Thought that it might then be the resistor and the motor
was only running full speed all the time.
7. Put everything back together again and it seems to be running fine.
8. Tested all the fan speeds from inside the vehicle and they operated as
Blower motor resistor must be good if the blower operates at all four speeds. Blower motor may have been dirty or it may be going bad (although I don't hear any noise that would indicate worn out bearings).
A new motor is about $30 around here and you can swap it out in 30 minutes or less. So, at this point I'm going to wait and see what happens. If it quits again, I'll just replace the motor and the resistor at the same time.
Many thanks to all who helped. Maybe this info will help someone else with a similar problem.
I think you should be able to spin the blower motor by hand easily. It sounds like the bearings are probably drying up and causing too much drag. Keep an eye on it because it can start drawing too much current and the connector can get pretty hot.
2004 F-250 SD, 4x4 FX4, 6.0L PSD
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I understand. I did not see any signs of heat whatsoever; but most small motors like this blower motor can be spun easily by hand. The fact that this one doesn't caught my attention right away. It has sealed bearings and no provision for lubrication so that's out. Vehicle has 83K, so with AC and heat, its probably seen some usage.
Now that I've identified the problem, I'll probably won't be able to forget about it and will replace the motor in a week or so for peace of mind, if nothing else. We have a three week fall trip in the NE with the RV coming up the last week of September and I want to know that I can rely on the AC and heat working.
Had similar issues (fan quit blowing - then blew intermittently on speed 2 & 3, but not 1 and 4, and after trying speed 4 it would not only shut off, but shut down for good and speed 2 & 3 quit working as well).
After 6+ hours of tracing issues & problems (and running both batteries dead) it all came down to a loose wiring harness connection going to the blower motor. Go figure.
Here in Southern California we just had a few days of 100+ degree weather heat (and a WHOLE BUNCH of wild fires), and I believe the plastic harness and housing got hot / pliable and made it very easy the connection came loose with just typical driving.
Point being ... CHECK THE WIRING HARNESS CONNECTION to the blower motor ... FIRST. I can tell you from first hand experience they DO, AND WILL, come loose.
Just my 2c. this information was very helpful for me so I thought I'd post for next guy.
2004 F250 Powerstroke 6.0 Diesel. AC and blower were working just fine. Really hot day parked after driving it for a couple of hours. When started the truck again the ac was not blowing any air. I could hear the CLUTCH FAN engaging when I would turn the dial but no air would come out.
Looked up this tread and tried the cheapest solution first. Changed the resistor- about 5 minutes total to change. No solution. Removed the ac blower motor and noticed complete free spin when turning by hand. Connected 12v directly to prongs to see if anything would happen, completely dead.
Ran to autoparts store and got replacement, installed it maybe 20 minutes total time to swap. tried it and viola, full blast.
Thanks for all that take the time to post problem and solutions- big help for beginners such a me. Gave me what to look for and replace.
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