Weak blower motor

[scott_williams2]

So I have a 97 k1500 with 5.7 vortec. Recently my blower motor started chirpin on low settings and it fluctuates. One minute it will be blowin really loud on high then a few minutes go by and it gets almost silent then it will go back to being loud. It also blows very weak from the vents. Never fooled wirh any problem like this is this the sounds of a bad blower motor or somethin else???

 

[HotWheelsBurban]

Could be the blower motor, but could also be the resistor or the dashboard switch. Several members have also had trouble with the connections on the switch and its wiring harness getting melted from overload. Had several switches go bad on my other 99 Burb. The current one hasn't worked right since I got it. Haven't had the time to get all into the dashboard and diagnose the problem. Also have to replace radio and CD player, so would like to do all at once. This is one of those issues that take time and patience to deal with.

 

[mtl111]

Sounds like the blower motor is getting old and tired. The chirping could be the bearings in the motor. I've been lucky and never had issues with my blower motor resistor or the switch on my Tahoe. I have had a resistor fail on an early Z71 Colorado I had. The blower would only work on high, no other speeds at all. Had to replace the harness for it too.
Get a motor, remove the old one and get the shop vac out as there is probably leaves, pine needles and crud that have found there way in there since these trucks don't have an in cabin air filter. Replacing the motor is easy.

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[Schurkey]

Why is this posted in the "Engine Performance" section?

So I have a 97 k1500 with 5.7 vortec. Recently my blower motor started chirpin on low settings

Common as dirt. The bushings on each end of the motor are dry. Since they're "non-serviceable", you need a new blower motor.

I have pulled older blower motors apart--which is not difficult, but they're not designed to be serviced--and lubed the bushings with lightweight white grease--Lubriplate 105, for example.

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and it fluctuates. One minute it will be blowin really loud on high then a few minutes go by and it gets almost silent then it will go back to being loud. It also blows very weak from the vents. Never fooled wirh any problem like this is this the sounds of a bad blower motor or somethin else???

Wild Guess: you've got air doors in the dash that aren't operating properly. Loud vs. quiet sounds like a recirculation door going crazy.

Sounds like the blower motor is getting old and tired. The chirping could be the bearings in the motor.

Almost certainly.

I've been lucky and never had issues with my blower motor resistor or the switch on my Tahoe. I have had a resistor fail on an early Z71 Colorado I had. The blower would only work on high, no other speeds at all. Had to replace the harness for it too.

My '97 had a newer, but defective blower motor. The motor drew so much current that I had smoke coming out the dash vents. It popped the 60-amp "Maxi Fuse", the 20-amp blower fuse, and the thermal fuse on the blower resistor pack., Replacing the two fuses got me "high" speed; but I didn't have the lower speeds unless I jumpered the thermal fuse on the resistor pack. Of course, I went the the Treasure Yard, and got a new blower resistor unit. It's no fun to replace the resistor pack, but it's do-able.

Get a motor, remove the old one and get the shop vac out as there is probably leaves, pine needles and crud that have found there way in there since these trucks don't have an in cabin air filter. Replacing the motor is easy.

It takes longer to do a decent job of getting the debris out of the A/C Evaporator and heater core than it does to replace the blower motor. Shop vac on the accessible side, compressed air "up" the heater outlet to dislodge crap from the other side. Again, no fun but do-able--but it's not a perfect system due to stuff lodging in the air fins of the evap and heater core; you can get "most" of it out but not all of it; and you still need to assure that the HVAC air doors and their actuators still work properly.[/QUOTE]