vibration in steering wheel when fan is turned on

[d-wreck08]

Hello,

I seem to be having an issue when engaging my fan. The truck seems to run perfectly fine until I turn the fan on. It instantly starts vibrating the steering wheel. The fan blows and the AC will blow cold but there is an instant and constant vibration at the wheel. Note: this happens while driving down the road and at a dead stop in park. I'm at a loss myself and not sure what other info to provide to better troubleshoot so just let me know if any other details will help.

Already pulled and cleaned the throttle body, with no noticable change.

Thanks for any advice!

 

[kickass audio]

Hit the A/C button to turn it off but keep the blower on full speed. Does it still shake? If it does then you are feeling the wheel shake from the blower motor probably being full of crud that is making it shake in the dash. If it does not then you probably have a bad air compressor. It could also be your radiator fan clutch thats bad, its hard to say for sure without troubleshooting further. BTW the throttle body has 0 affect on this other than if you have the AC on at idle and the truck wants to stall.

 

[d-wreck08]

Thanks for the quick reply. The wheel vibrates the same whether I have the AC on or off. Also if I put the fan at the lowest settings the vibration is almost gone and gets worse as I turn the fan up.

The cluth fan was my guess at first to but the truck runs completely fine with the fan off, both just beating around town and at full operating tempature on country roads.

AC compressor was replaced about a year ago and I did the throttle body "just becasue" it was filthy.

Any addition insight would be great!

 

[Hypnotoad]

Check and see if there is anything like mud stuck to the fan blades.

 

[d-wreck08]

I'm thinking the blower motor is the probelm. The noise/vibration seems to be directly in the dash. Looking under the hood while trying to find any additional noise or vibration seems to be a lost cause, nothing seems out of place there, no engine vibration and no visiable fan issues.

Thanks for all the details so far!

 

[The_Roadie]

Just a little confusion between "fan" and "blower". I agree it MUST be the HVAC blower, which is held in to the plenum by three screws. It's behind and below the glove box. The under-dash closeout panel and the glove box need to come out.

The definitive test would have been to run the HVAC blower with the engine off.

50-50 chance you're going to find some dead mice fragments in there - so be prepared mentally before you drop the blower motor.

 

[kickass audio]

what roadie said. My dad had a blower bearing that was shot on his HVAC system and the dash would vibrate so bad at high fan speeds it was so annoying. When he replaced the fan it instantly was quieter and it felt to blow out more air too since it was a whole new assembly with the cage and motor in one piece. Just check it for the heck of it, it may just be full of debris and if it is thats easy, get a shop vac and suck out as much of the crap as you can. Then for the fan itself double check that the bearing didn't get ruined while it was full of junk. You can also try to take the fan out of the truck and apply 12v directly to the pins on the fan if you want after its clean to see if it has a bad wobble to it.

 

[The_Roadie]

Just a little warning for bench testing - those sorts of 12V motors have a huge starting torque and can rip the motor out of your hands if you're not braced. Then the spinning bits can do some damage to you or the shop.

 

[d-wreck08]

Guys,

Thanks for all the good info. There was a mouse in the blower motor causing all the problems. I poped it out and removed the mouse, acorn and leaf problem resolved.

As for now I did not test it any further as this problem just started yesterday and I only ran the blower for maybe a minute or 2 like that during troubleshooting so im not terribly concerend about perminate damage.

I am traveling now and away from home anyway, burnout from a long weekend and car troubles were the last thing I wanted to deal with. The obvious test was to do as roadie said and turned on the blower with the car off, exact same problem persisted.

Thanks again for the quick responses and advice!

 

[kickass audio]

you're welcome man! IT usually is an easy fix for things like this and I would think you would be alright with it as long as you didn't leave it like this for a long time. Enjoy your traveling with a working HVAC system now

 

[IllogicTC]

Guys,

Thanks for all the good info. There was a mouse in the blower motor causing all the problems. I poped it out and removed the mouse, acorn and leaf problem resolved.

As for now I did not test it any further as this problem just started yesterday and I only ran the blower for maybe a minute or 2 like that during troubleshooting so im not terribly concerend about perminate damage.

I am traveling now and away from home anyway, burnout from a long weekend and car troubles were the last thing I wanted to deal with. The obvious test was to do as roadie said and turned on the blower with the car off, exact same problem persisted.

Thanks again for the quick responses and advice!

Just be glad it was just a mouse. You'd be surprised how easy it is to find pictures of whole mouse nests built into HVAC systems, or even air intakes! Seen several photos where rats were hoarding dog food in the air box of cars.

 

[Mounce]

Had a mouse nest in our Silverado a few years ago. It was in the intake box before the filter, mostly fiberglass insulation, it'd been there a while though, no mice were around.

 

[RayGumm]

Hantavirus! Mmmm smell the sickness blowing out of the vents!

 

[Sparky]

Rodents are strange creatures. When the previous owner still had my Camaro he had it parked all winter in his garage and mice filled the tailpipes with corn kernels from the nearby field. So in the spring when he started the car up for the first time it blew a bunch of corn across the garage lol.