Car Heater Only Work On High

I Was Wondering Where The Resister Is Because The Heat Only Works When It Is Full Blast I Have 97 Gtp OR CAN IT BE THE SWITCH

Do you have the HVAC with manual controls or digital climate control?

Manual has the blower motor resistor and digital has a blower motor control module.

The 97 Grand Prix has a hi-speed relay which happens to be located with the blower motor resistor or control module.

Here is a link showing a BMR:

http://www.clubgp.com/newforum/tm.asp?m=2075435&appid=&p=&mpage=1&key=blower%2Cmotor%2Cresistor%2Cwrite&language=single&tmode=&smode=&s=&cookie&cookieCheck=389562974&cookie

The AC-Delco part number for the manual control blower resistor is 15-80571 (GM#89018643). Dealer retail is $38.65. If you have any Delco distributors in your area, they will sell it cheaper than the dealer. We sell it for $20, just for reference.