I had a similar problem with my 2004 gp, it was the blower motor resistor that was faulty. Its located under the passenger side dash. There is three clips that hold the bottom portion of your dash in place, they simply pop out make sure you keep them. Once open you will see your blower motor housing, if you look towrds the fire wall you will see the resistor in behind the blower motor. You'll need to break the factory plastic rivets, to remove the resistor out of its housing. Once the resistor is free it's just a matter of removing the quick connect coupling,and replacing with a new one. You will need to get two new screws to replace the plastic rivets. Takes about 20min. To do very easy....
I would also suggest, that you remove your blower motor. It's been known for water to enter the blower motor housing and burn out your blower motor. It just happend to me!!! The best time to look is after it rains....
I would also suggest, that you remove your blower motor. It's been known for water to enter the blower motor housing and burn out your blower motor. It just happend to me!!! The best time to look is after it rains....