AC Fan or Switch

[threejacks]

2 or 3 days ago I started my truck and AC fan would not blow. I moved AC/Heat selector to all positions, restarted truck, checked AC compressor, and no fan. I got on Interstate and as I got up to speed and still moving selector and fan switch to all positions, nothing changed. Then all of a sudden everything started working. Worked every time since, until this morning. After 3 or 4 stops, got in truck and started and fan would not blow. When driving at road speeds cool air would come out but was getting no help from fan. I stopped at parts store and tech unplugged fan connection to check fan and had power going to fan, felt I had a bad fan, plugged back in with power on and fan started working and worked ever since. Any ideas on what my be wrong?

 

[powerboatr]

A few things come to mind.
the big ugly resistor pack on the fan housing under the hood
the switch itself after 300k plus miles it might be worn out
loose fuse???
loose electrical connection
does fan make funny noises ?

my bet would be the switch.

2 or 3 days ago I started my truck and AC fan would not blow. I moved AC/Heat selector to all positions, restarted truck, checked AC compressor, and no fan. I got on Interstate and as I got up to speed and still moving selector and fan switch to all positions, nothing changed. Then all of a sudden everything started working. Worked every time since, until this morning. After 3 or 4 stops, got in truck and started and fan would not blow. When driving at road speeds cool air would come out but was getting no help from fan. I stopped at parts store and tech unplugged fan connection to check fan and had power going to fan, felt I had a bad fan, plugged back in with power on and fan started working and worked ever since. Any ideas on what my be wrong?

 

[kenh]

OR, the aforesaid connector was loose, and/or dirty pins.
and unplug/plug cured it.
IIRC, the resistor is bypassed in top speed, so should not effect high gear running.

 

[threejacks]

Problem got worse and fan finally quit. Installed new fan motor and getting more air on low setting than I have in months. It must have been getting weaker for some time and had not noticed the difference until I put new fan motor. Thanks for replys.