Heater Blower Motor
 

I Have a ptoblem with my 1990 teg heater. its pretty wierd and i cant figure it out. Im wondering if anyone has had the same problem. Basically my blower fan isent working properly. when i turn the switch on for the blower it shuts off my deck and it still doesent work. so i disconected me deck and checked the wiring for any wire thats exposed but everything is solid. even with my deck disconected aswell as the wiring harness it still doesent work. i even tried connecting the stock tape deck and still the same. I figure theres a short somwhere or there might be a problem with the resistors for the fan switch. the thing is sometimes it does turn on momentarily or even stay on for 10 mins so i know the blower motor itslf works fine. does anyone have any ideas ?

thx