Air conditioner related howling?

[ECKSJAY]

Tried to search but didn't know what to call the noise. ;) Please bear with me.

I've a howling noise coming from behind the passenger side dash that is extremely loud. It seems to come and go anytime any AC-related feature is being used. It's audible from the outside of the Jeep and it's pretty embarrassing, not to mention an annoyance to my passengers and I.

So what's behind that dash panel? I see the HVAC 'box' back there and it's vibrating horribly along with this howl.
Thanks!

[01xj]

Originally posted by ECKSJAY

I've a howling noise coming from behind the passenger side dash that is extremely loud........I see the HVAC 'box' back there and it's vibrating horribly along with this howl.
Thanks!

I would first rule out the blower motor. The FSM suggests
unplugging the blower motor wiring connector, and then
operating the HVAC system normally. If the noise goes away -
the blower motor is unbalanced, mounted incorrectly, or is faulty.

Good luck!

[RichP]

I have had a couple of blower fans go, one in my S-10 and the other in the trooper, howling pretty well describes it. I just let it howl till it quit then put in a new fan on the S, when the trooper started I ordered one, got it 2 days later and didn't wait, just stuck the replacement in. The bearings were dry on both of them. I seem to remember they were like $50 or so.

[Lewis]

I think that you will find that your a/c compressor is not cycling off like it normally should about 3 to 4 times a minute.
I just went through the same awful noise with my Cherokee.
You might be overcharged on freon.
My a/c started making this same noise after adding too much R134.I released some of the r134 and it works fine now.

[ECKSJAY]

Originally posted by 01xj
I would first rule out the blower motor. The FSM suggests
unplugging the blower motor wiring connector, and then
operating the HVAC system normally. If the noise goes away -
the blower motor is unbalanced, mounted incorrectly, or is faulty.

Good luck!

I'll give that a shot today. So I'm assuming by this that there's a separate blower motor that only operates when the AC is kicked on?

[RichP]

No, we are talking about the fan thats in that mixing box behind the dash, what he means is 'rule that out first' but I think that you will find out that that is your problem. If the box is vibrating then it is vibrating from the motor that drives the fan. It looks like a bear, according to my 98's FSM you need to drain the system, remove the accumulator [that tank looking thing with the tube coming out of it] which means draining the system of freon. Then putting it all back together and having it evacuated and recharged. Easy job for a shop that works with AC stuff. Personally I'd loosen some stuff up and see if I could squeeze that blower motor out without removing the accumlator but it's a tight fit, depends on how far the squirrel cage goes inside.

Does your howling change with the speed of the fan, or does it go away after a while or stay the whole time ??

[ECKSJAY]

Originally posted by RichP
Does your howling change with the speed of the fan, or does it go away after a while or stay the whole time ??

Well no it's intermittent...and from my experience it DOES sound like bad fan bearings. So if that's a separate fan back there then it must be it. I'll troubleshoot later though.

Thanks for the help and confirmation, folks. I'll post results later.

[afjeep2082]

any conclusion to the problem?? I have the same exact thing goin on and it is so damn enoying

[ECKSJAY]

It just went away. :dunno:

[ghettocruiser]

i second the overcharging... I suspected my blower motor...but that wasnt it. It only seemed to do it while off the throttle too. but it went away so thats good...

justin

[red91]

It just went away. :dunno:


Squirrels.