I’ve noticed lately that the blower motor surges. Doesn’t matter what setting it is on, hot or cold, I hear a click and it will surge RPM a little bit (I can hear it because it has gotten noisy). I can also see a noticable bounce in my engine RPM when this happens (slight, but it’s there I can hear it in my muffler as well). Any ideas?
Let me ask if the surge is in time with the turn signals or wipers? Otherwise I’m betting on the resistor pack mounted in the blower has been whacked and the coils are overlaying each other, shorting and fusing sporadically.
Nope it’s just a continuous surge, every 5 seconds or so I can hear it slow down, then speed up, then slow down, then speed up. There is a slight click accompanying each surge.
I was just having that exact problem a few weeks ago but it mysteriously went away on its own. I’m still curious as to what caused it. Hopefully it won’t come back. 
Pull your cabin air cowls and see if you’ve got a mess collected in the squirrel cage. Still think its your resistor pack or ground.:werd:
It almost seemed like a damper was stuck or something. If there was someting stuck in the squirrel cage it would be a very rapid click (kind of like a card stuck in your bike spokes). In our cases it would only click every 5 seconds or so in relation to the surging. You can hear and feel the fan blowing as if were normal other than the surging.
Like I said it went away. I’m not sure if it was related but it went away after I had disconnected the battery and let the car sit a few days.
If you have the FSM, I’d trace the ground for the blower motor and refurb it. The blower resistor is a constant. What you’ve got sounds like a relay that cycles on and off. If that relay uses the same ground and the ground is corroded then I think you’ve found your problem. Might want to list this in the electrical area(ask a monitor). Lots of good brains over there.:read:
:manual:
Good idea, thanks guys.