Your blower motor resister needs replaced. Basically, the different speeds are created by different amounts of power going to the motor. The more resistance, the less power, the slower the motor runs. On high, there is no resistance. The motor gets the full 12 volts from the battery. As a result, it is the only speed that will work becase it doesn't go through the resister.
It's not an expensive part and it's easy to install.
If you have other questions, let me know.
Joe
SPONSORED LINKS
Saturday, December 26th, 2009 AT 10:40 PM