Blower motor works intermittently

Check the blower motor and blower motor resistor. They are both next to each other under the dash near the firewall behind the glove box. Look for lose wires and melted plugs. If the blower works but only on high speed only it's going to need the blower motor resistor replaced.

Check the brushes.

Can't they are sealed units.

I had the same problem. and took the motor apart and checked the brushes.

Cool(no pun intended)! Where did you find replacement brushes at?

To TransAm77 - I've had this issue on a few occasions with my Century and offer my experiences for your critique: 1. If blower only works on high, then likely it's the resistor on the motor but not always. 2. If the blower works at various speeds but doesn't always, then it could be the motor going bad or it could be a poor electrical connection. a. I've run a jumper wire from power to the motor bypassing the controls and the resistor. If the motor works on every attempt I start looking for bad connections either from the fan control to the resistor or the resistor to the motor. One time it was just a loose wire - simple fix. I've replaced the resistor when the blower only worked on high and the system was restored. When it wouldn't run at all, even with the jumper wire, I've replaced the blower motor and it worked fine. One time however, it only worked on high and intermittently. I replaced the resistor with no change in performance. Fortunately, my parts store allowed me to return the resistor. (That's pretty rare with electrical parts.) Upon further inspection I found the problem to be a faulty fan control switch on the dash. I pulled the switch out, took it apart (not recommended) and found the contacts to be oxidized. After I cleaned up the contacts and put it all back together, it worked fine. I recommend, if it is the blower control, replace the switch because it wasn't made to take apart and in most cases you'll likely have a less than fully functional switch after reassembling.

Yea what RunTowin said! LOL nice detailed answer.

My local Hardware store sell brushes. I had to customize them but less than $3. Sometimes re positioning the brushes gives the motor more life.

Ahh good to know, good to know.

It can also depend on the type of A/C in your car. The standard unit has a resistor The Deluxe/automatic A/C (the one where you set the temp number and the car maintains that temp) will have a control module. It has a heat sink and in in the ductwork, I am attaching a picture of one from a 1990 Buick, they are different but do the same function. It is #1 in the picture

The solution I used may sound strange but here it is. I replaced the extremely dirty cabin filter. The blower motor now works 100% of the time. If your cabin filter looks even somewhat dirty, remove it. If the blower motor then works for the next couple of days, install a new filter. This solution is quick, very easy and cheap (about $20). I truly do not understand why this works, but it did! The testing of the solution spanned about 40 contiguous hours, with air temperatures of from 39 F. to 112 F. and altitudes of from 2000 to 6600 ft. During this time the car engine was started and stopped 15 times. Good Luck!

I have the same problem with the fan intermittently. I thought that it may be the cabin filter. When I had my car serviced the dealer said that my car is not equipped with a cabin filter. Can this be true ?

Cabin air filter, depends on the year of your car and the level of A/C it has. Just worked on a 2003 Buick Rendezvous and it had one, but an older body design might not get one until there was a redesign. Also GM had regular A/c and they had automatic A/c...automatic A/C was the deluxe version where you set the temp and the controls maintained that temp...the Automatic A/c units got the cabin air filter first. Since I don't work on newer cars.....I have never heard about the cabin air filter keeping the blower from working. A dirty filter may greatly restrict the air flow and you don't feel much output. If you have a non-cabin filter car......you may have debris blocking the evaporator. The car makers added the cabin air filter because of this problem......all the air goes thru the evaporator...during A/C operation it is damp and dust, pollen, animal hair etc sticks to it and will eventually restrict the flow thru the evaporator... on the Riviera (picture above) when you remove the blower fan module you can see the front of the evaporator....if it is dirty it needs to be cleaned to improve A/C and heat operation. I made an adaptor for my shop vac to suck the crap off the front of the evaporator .

my 05 works when you smack the area under dash, any ideas?

My 2005 LeSabre has same problem. I just tapthe blower and it's on but if I turn off car I need to tap again. Still looking for a solution for poor, oldster and her car!