My A/C, vent fan (blower motor) keeps going in and out. Does not do it all the time, but when it goes out, it will come back on after a few moments, but will not run full speed. If you try to adjust the speed, it just cuts off again. Does anyone have any ideas of what is causing this.

 

Might be a couple of things in conjunction......I would suspect the Blower Motor Resistor Assy and the Blower Motor Switch. The Resistor pack contains a thermal cutout device that would explain it going on and off, and the Switch would explain it not working at all in one position.

hth
Vaya con Dios,
Chuck, CABGx3

 

^ What he said...

 

Thanks for the response. LOL Still chasing it though. Hasn't done it since I posred, and the outside temps dropped below 100. I need to catch it the next time it does it to check some things, but like I sais, been working fine.

 

I have the same or similiar problem with my 250 super duty. Blower motor cuts on and off randomly. I replaced the resistor pack and it didnt make any difference.

When it works the fan will blow in all speeds. Could the blower motor itself be going out or is the switch more likely?

Thanks for any input.

 

After a little more troubleshooting, I found that my problem was a bad connection at the plug for the blowere motor. Check the contacts inside the plug for dirt and loose connection. I re crimped mine and have had no problems since.

 

I've been having ac/heater issues with my 2009 f150 lariat for the past year. I have the dual zone climate control. My mechanic troubleshooted and mentioned that I needed to replace the dual zone automatic temperature control switch/module bc I was controlling ac on driver side, however, passenger side had minor cool air. On the other hand, in winter, driver side had no heat but passenger side had heat. My blower presented a problem about two months ago and replaced the blower resistor, it worked fine until a couple of days ago when all of the sudden the blower went out. It would occasionally come on when I hit a bump or by chance, came on when I started the vehicle. I think I'm going to purchase a new blower motor tomorrow and see if that works. If not, I guess I'll have to replace the climate control module. Anyone, else have this experience?

 

Me too! See thread I just bumped.

 

I have a similar and yet different issue. Weeks ago I replaced the resistor pack (it needed it), and everything worked fine... for awhile.

Now none of the (front) fan speeds work, but the rear fan controls do work. Also, the front AC / vent selector switch appears to work for pumping AC to the rear, and the rear fan speeds switch works while the front fan speed switch makes no difference (nothing comes out front vents)..

I'm going to re-check connectors, but am guessing my front speed selector switch might be corroded or otherwise malfunctioning. Anyone else have this experience?

 

Having the same exact problem with my 2000 Excursion. Any luck finding a solution?

 

Turned out my blower motor was bad. So I replaced it and everything works.

Learned a good lesson: never buy the "lifetime warranty" part if you need to rely upon it working.

 

Many thanks.

 

If the connections on the blower motor are bad, melted or burnt the blower motor is most likely going out, drawing too much power, a somewhat common problem in higher mileage trucks. This can also damage other parts of the system if ignored.

 

I will check the connections. There has been a great deal of condensation over near the blower motor. (South Florida summer) Seems like more than usual. It probably has infiltrated the resistor and blower motor area. Thank you very much.

 

This is a reply to a thread but is good for everyone . I am a troubleshooter of electrical refrigeration , heating , auto motive , etc. electrician 43 years .
I want all to know that when terminals are burned up it is due to a loose connection...nothing else . If there were too much current the whole wire would melt. Regarding motors gong out. : either bearings are bad or windings open or melt (burn)together. the relation mentioned above of higher mileage trucks is just due to a long time of heating of the loose connections. The heating is caused by arcing which acts like electric welding on a small scale. I hope this helps you all sometime in your troubleshooting.