| [GMCnet] Fan motor [message #356320] |
Wed, 01 July 2020 18:28  |
Hanson Email
Messages: 110
Registered: March 2020
Karma: -1
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Senior Member |
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I have an electrical problem and I'm sure it will bite my tush fairly soon.
I have always had a slight high pitch tone with my HVAC fan. It runs on low
constantly in my unit and carries that same tone thru the first 3 and
becomes louder when on High mode. It varies slightly with acceleration of
the motor. And no, it's not the alternator but sounds like that. Well, today
when off, it started screaming like a banchee. I stopped and turned the
engine off then back on and the screaming went away. Definitely in the fan
motor. So what's failing? Seems like it is getting a different electrical
load which makes it squeal.
Dean Hanson
75 Avion, returning to life from a 10 year sleep. I do have one year of
running about 30 miles a month, while I fix up those twin beds.
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| Re: [GMCnet] Fan motor [message #356330 is a reply to message #356320] |
Wed, 01 July 2020 18:48  |
stu@97381.com, Emery
Messages: 232
Registered: June 2020
Karma: 2
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Senior Member |
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It’s probably a dry shaft bearing. You might take it apart and grease the shaft or, perhaps get a new blower motor.
Emery Stora
> On Jul 1, 2020, at 5:29 PM, Hanson Email via Gmclist wrote:
>
> I have an electrical problem and I'm sure it will bite my tush fairly soon.
>
>
>
> I have always had a slight high pitch tone with my HVAC fan. It runs on low
> constantly in my unit and carries that same tone thru the first 3 and
> becomes louder when on High mode. It varies slightly with acceleration of
> the motor. And no, it's not the alternator but sounds like that. Well, today
> when off, it started screaming like a banchee. I stopped and turned the
> engine off then back on and the screaming went away. Definitely in the fan
> motor. So what's failing? Seems like it is getting a different electrical
> load which makes it squeal.
>
>
>
> Dean Hanson
>
> 75 Avion, returning to life from a 10 year sleep. I do have one year of
> running about 30 miles a month, while I fix up those twin beds.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] Fan motor [message #356332 is a reply to message #356320] |
Wed, 01 July 2020 19:10 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Dean,
Emery's given you the solutions to the dry bearings. But, in case you
don't know how to stop that fan from ALWAYS running, here's how: On the
left (driver's) side of the under-hood HVAC box there's a plug which
connects to the set of resistors which control the fan motor's speed. If
you unplug that connector and bend down the protruding 1/4" connection pin
which corresponds to the Yellow wire in the bundle, you'll eliminate the
always-running condition. And if you ever add an accessory which needs
power in the IGN position, just connect it to that now-unused Yellow wire.
Ken H.
On Wed, Jul 1, 2020 at 7:29 PM Hanson Email via Gmclist <
gmclist@list.gmcnet.org> wrote:
> I have an electrical problem and I'm sure it will bite my tush fairly soon.
>
>
>
> I have always had a slight high pitch tone with my HVAC fan. It runs on low
> constantly in my unit and carries that same tone thru the first 3 and
> becomes louder when on High mode. It varies slightly with acceleration of
> the motor. And no, it's not the alternator but sounds like that. Well,
> today
> when off, it started screaming like a banchee. I stopped and turned the
> engine off then back on and the screaming went away. Definitely in the fan
> motor. So what's failing? Seems like it is getting a different electrical
> load which makes it squeal.
>
>
>
> Dean Hanson
>
> 75 Avion, returning to life from a 10 year sleep. I do have one year of
> running about 30 miles a month, while I fix up those twin beds.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Fan motor [message #356342 is a reply to message #356320] |
Wed, 01 July 2020 22:33 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Replace the fan motor. It is a common GM item. The last one I replaced, I pulled into an Auto Zone in Fallon, Nevada, replaced it in about 10 minutes and went on my way. Get the one with the new fan already installed on the motor if possible.
You also could try lubing the bearings as Ken H. and Emery.
I wish the one on my wife's Jimmy was that easy to replace.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Fan motor [message #356354 is a reply to message #356342] |
Thu, 02 July 2020 08:02 |
powwerjon
Messages: 849
Registered: March 2013
Karma: -2
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Senior Member |
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To All,
As Ken H and Emery indicated you could add oil to the dried out bronze oil impregnated bearings, but in my experience that would only prevent failure in the future. When we got our first GMC we were destroying the AC relay AR109 and or the wiring between the relay and the blower about every 12 to 14 months (1998 thru 2003). Check the Current draw on the blower motor and it was much more that expected. I changed out the fan motor with a new one and AR109 relay was still in the coach when it was sold in 2011.
Ken B suggestion to change out the motor and that is best bang for the buck and time. The Blower motor you want to buy is a PM102 part number. That number is good at almost all of the big box stores or does cross to their part number. It cost the better part of $23. You must reuse the blower cage. I have alway found them easy to push out the blower shaft, be sure to remove the nut. It is typically a white plastic squirrel cage wheel and this is your time to clean it and the area where it fits into the blow housing.
https://www.autozone.com/cooling-heating-and-climate-control/a-c-heater-blower-motor/continental-vdo-new-a-c-heater-blower-motor-pm102/141515_434469_6 648&searchText=pm102
https://shop.advanceautoparts.com/p/carquest-flanged-vented-cw-blower-motor-w-o-wheel-35587/5012066-P?searchTerm=35587
https://www.napaonline.com/en/p/BK_6551039?keywordInput=bk6551039
https://www.oreillyauto.com/detail/b/murray-climate-control-5217/lighting---electrical-16777/motors---actuators-25143/blower-motor-12457/0da7cd2eedaa/ murray-climate-control-blower-motor/pm102/4781787?q=pm102&pos=0
The blower cage is available at advance auto under part number 35448, just need to compare the new with the old for fit.
https://shop.advanceautoparts.com/p/carquest-standard-rotation-blower-motor-wheel-35448/18891338-P?searchTerm=35448
The blower motor was my personal experience, yours could vary!
J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan
> On Jul 1, 2020, at 11:33 PM, Ken Burton via Gmclist wrote:
>
> Replace the fan motor. It is a common GM item. The last one I replaced, I pulled into an Auto Zone in Fallon, Nevada, replaced it in about 10
> minutes and went on my way. Get the one with the new fan already installed on the motor if possible.
>
> You also could try lubing the bearings as Ken H. and Emery.
>
> I wish the one on my wife's Jimmy was that easy to replace.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
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| Re: [GMCnet] Fan motor [message #356363 is a reply to message #356320] |
Thu, 02 July 2020 12:01 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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I have revived several by blowing out dirt with blow gun, flushing commutator with Caig F5 spray, then a couple drops with zoom spout oiler on each bearing. The F5 flushes and leaves behind light lube. Designed for moving contacts in fact old name was “moving contact lubricant”. If the brushes are worn or it was run long with dry bearings, replace.
John Lebetski
Woodstock, IL
77 Eleganza II
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