Dodge Repair: 1999 Dodge Van A/C fan, blower motor resistor, dodge van

Question
The blower quit working a month ago.  Sometimes if I hit a pothole or RR track just right it comes on and contiutes to work until I turn the vehicle off.  Then I have to find another pothole.  Temp guage and air positions work fine.  When the fan is on it works at all fan speeds.  The fan for the back of the van works just fine.    THANKS     KEZ

Answer
This is kind of a strange one but SHOULD be easy to find with a bit of electrical inspection.

The fact that it works in multiple speeds rules out the blower motor resistor, a common part that fails.  This doesn't rule out the connection and it should be check (right strut tower area going in to the firewall).  

Next we could more than likely rule out an excessive current draw like a motor going bad because it doesn't pop a fuse.  If the fuse popped then you would never have it come back on.  However, this doesn't rule out a bad section in the blower motor itself.  Removal of the fan and moving the fan wheel while the fan is in the on position may help determine if the motor is siezing up or not.

Next thing to check would be to make sure that the vehicle has power and ground at the blower motor itself the entire time the switch is in the on position regardless of whether or not the blower works.  If power or ground is not present then you must search that particular side in order to find out why it's not present.  

The fan motor circuit is not very complicated and a decent mechanic SHOULD be able to figure this part out pretty quickly.  The at-home or shade-tree will have a bit more trouble depending on access to wiring diagrams and grasp of electronics.
Doug