Auto A/C front blower shuts off on High setting (all other speed good)

[sjwelds]

http://www.expeditionforum.com/threads/weird-ac-fan-issue.32522/

My experiences, FWIW

 

[Space Monkey]

Here is an update:

I replaced both the blower motor and the speed controller module with motorcraft parts and it worked for 2 weeks. Pulled the connector and it is burned again on the yellow-blue wire. All of the parts were brand new and I soldered/heat shrunk the new pigtail in. I failed to mention that my truck is the limited and has the dual air with digital control panel, so this is not a "resistor pack". I have ordered the factory wiring diagram book so I can properly trace the wires.

 

[ExpeditionAndy]

You might want to make sure that you have a good ground. Somewhere I read something about a weak or broken ground could cause overheating. It's just a thought.

 

[stamp11127]

When a connector continually melts as in your case the heat is being generated at the connection point or the point where the terminal is crimped to the wire. The heat is a by product of resistance at that point

If you still have the old controller solder a jumper wire directly to the lug on the board and to the yellow/blue wire using the same gauge or larger wire. Plug in and see if it works. If it does you may consider modification to a larger gauge for the entire run of the yellow/blue wire and modified connection to the controller.

 

[Adieu]

Mine cuts out at idle/crawl in "D" thru traffic after a while if a bunch of current draws on battery like radio, HIDs, multiple devices on chargers, and high power fogs are all on... its a too much power drawn at low engine RPM thing. when i ignored that for a while, once even needed a jump.


Battery gauge didnt move much btw....

PS cheapest $30 or so walmart battery tho

 

[Space Monkey]

I got the electrical diagram book and am starting the "why is the wire burning hot" troubleshooting.
Direction wise, I thought the power came from the blower motor speed control, but it goes through it instead to ground..pin 2 (YE-BU) is the one melting. So maybe have a bad connection there even though everything is brand new.

 

[Copper93]

Did you ever figure this out? 2013 expy, the blower motor went out completely and I replaced the speed controller. Now I have speeds 1-6 but 7 shuts down. I can back it down to 6 and it will start blowing again.

 

[swamper]

I'm having the same problem as copper93. Replaced blower & blower speed module. I don't see any burnt wires. Checked alternator & it puts out a consistent 14v. It will blow on speed 7 with engine off.

 

[Bloodyknuckles1]

I have a 2008 Eddie Bauer Expedition with dual automatic controls. I'm having the same problem as copper93. I replaced the blower motor and resistor (control module), and all speeds work fine but the highest. I don't see any burnt wires. Checked alternator & it puts out a consistent 14v. It will blow on speed 7 with engine off. I read somewhere about resetting the PCM, has anyone done this and did it work. Any ideas, Please!

 

[stilbo]

2015 XLT...
Highest fan speed on front HVAC fan stays on for about 5-10 seconds then shuts down.
Changing fan speed via +\- selector button to any speed lower than maximum allows ran resumption at any speeds selected.
Resistor pack, motor and cable connector replaced by dealer before I bought it.