Hi All,

I have a 98 Blazer and the other day the Blower Motor went from working perfectly to bareley blowing... ONLY on the High Setting. The 1/2/3 work fine but when you switch it to High it runs fine for about 5-7 seconds and then goes to to maybe a 1 setting ...very low rpm's. Ive checked all the fuses and replaced the Speed Resistor unit with a new one but still have the problem.

Could it be the Relay itself?

The fan motor is about a year old if that helps.

if more info is needed please let me know...I didnt want to flood this post with unessessary info.

Thanks!

 

Rule of thumb with blower diagnosis is:


Speeds 1, 2, and 3 are controlled by the resistor. If any one or more of them fail, the resistor is most likely the problem.
If high speed fails, the relay is most likely the problem.

 

almost sounds like the motor could be overheating/seizing..... have you tried plugging 12v dc direct from the battery to the motor power connector? typically when the resistor pack fails, you'd end up with full power or nothing at all.

 

Thanks for the info, I have not jumped a direct 12VDC to the motor yet, its fairly new and turns smoothly but guess it could be defective. Im going to throw a relay at it later today and see if that corrects the problem. Will post the outcome

 

Well the relay was the problem! Sure is nice to have that working again seeing how its going to start getting hot again.

Thanks again for the tips...much appreciated