When I turn on the a/c the blower will not run. Days back I would hit the dashboard and it would run but not anymore.

It could be the blower motor resistor or even the blower motor. If you hear the air blowing with the glove box open but, none can be felt, check the cabin air filter. This filter can become clogged with leaves and debris that enter the HVAC box. The filter is located underneath the dash near the blower motor. The reason for some air flow after you hit the dash is it must be clogged and it clears enough to allow for the small amount of air to pass.

this sounds like the blower motor is bad causing it to stop when going over a bump. the brushes in the motor may be worn out.

bad or loose heater switch behind dash...loose wires on switch...blower motor fuse loose in fuse box...

This is caused by a defective blower fan motor, replace it.
Removing the Blower Motor

• 4Remove all four of the screws from the glove box with your Philips screwdriver and set them aside.
  
• 5Slowly remove the glove box from the dashboard. Make sure that no wires get caught or stuck. Place the glove box and its screws to the side of your work area so that they're out of the way.
  
• 6Locate the blower motor under the dashboard. It will be shaped like a small circle, and is about as big as a saucer used to hold a teacup.
  
• 7Unplug the wiring harness from the blower motor. Use the painter's tape to mark the wire, then temporarily tuck it out of the way under the dashboard.
  
• 8Remove the three screws that hold the blower motor in place.
  
• 9Carefully remove the old blower motor and place it to the side of your work area.
  

Installing the Blower Motor

• 10Inspect the new blower motor to make sure that it isn't damaged. Check both blower motors side by side to also make sure that they are identical parts. Place the new blower motor back into the same exact position as the old one. Make sure that all three of the screw holes line up correctly with the new blower motor's screw holes.
  
• 11Secure the blower motor by returning all three screws using your Philips screwdriver. Be careful not to strip the screws. One quarter turn past hand-tight will be enough to secure the blower motor.
  
• 12Remove the painter's tape from the wiring harness and plug it back into the new blower motor.
  
• 13Carefully slide the glove box back into position while making sure no other wires are caught or tangled, and resecure it with its screws.
  
• 14Remove the black tape from the battery cable's metal terminal and reattach the cable to the car battery. Start your car and test out the new blower motor on all of its air settings to make sure it works properly.
  

Sounds like a bad relay

Hi, an intermittent blower can be caused by either the switch or the motor itself. To find which it is, try messing with the switch to see if it will misbehave. If not, then the next time it doesn't work, try hitting the motor. Unfortunately your blower is behind the glove box, but maybe you can just pull the glove box past its stops and reach back to hit the motor with your fist. It hitting it makes it start, the motor has a dead spot on the commutator and should be replaced. Please let me know if you have any questions, and thanks for using FixYa.

It does sound like a bad switch --- possibly arcing and overheating -- or it could be dirty / corroded contacts on the switch or in the wiring harness connector.

The switch should come out fairly easily after getting access to the back of it -- it probably has tabs on it which when pressed in will allow the switch to come out the front.

Charlie


P.S. The blower motor resistor would not cause an overheating switch -- a bad resistor would at worst allow maximum current to go through the switch -- the switch is designed to run the blower at full speed (maximum current) w/o overheating...

try taping on the blower motor with a mallet. if it starts when u tap it, its probably the blower motor itself. if it doesnt it is most likely the blower motor resistor. let me know which one you need to find

Check your fuses.

Look for blower motor up under dash on passenger side & check for voltage getting to motor connector, if not, start backtracking perhaps to a resistor or connection back to switch. (temper,temper!) Sorry, couldn't resist.