Fan Blower control works intermittently

[mike]

Hello All, I hope everyone's summer is off to a good start.

I did a search here and found several posts dating back to 2012 regardis to why a fan blower motor quits working. Mine started acting up yesterday, I
was driving along with the AC on and the switch in the HIGH position, I have a 1975 Royale by Coachmen.

If I leave the switch in the HIGH position I noticed it will work for a few minutes then the fan quits, several minutes later the fan comes on and a
few minutes later it quits again.

Where should I begin trying to locate what might be causing this intermittent function?

Thanks,
Mike

 

[sean kidd]

Instead of a fuse, you probably have a thermal breaker...it heats up, opens the circuit..;cools down and closes atarting the fan again. Your fan is
either failing, or something obstructing the fan, it's pretty easy to pull the fan and see if it spins freely...otherwise you may have a loose
connection, causing the wire to heat up. Remember, the high speed fan runs only when the alternator is spinning, low and medium run from the battery.
--
Sean and Stephanie
73 Ex-CanyonLands 26' #317 "Oliver"
Hubler 1-Ton, Quad-Bags, Rear Disc, Reaction Arms, P.Huber TBs, 3.70:1 LSD Honda 6500 inverter gen.

Colonial Travelers

 

[Ken H.]

Mike,

The fan is badly subject to critter pollution so you probably need to
remove it and clean it; if it's loaded, it will draw excess current and
trip the breaker.

Also, the only ground for the motor is through a ground wire under one of
its mounting screws, which are screwed into the fiberglass blower housing.
In other words, it's VERY subject to loosening. It should have a star
washer and corrosion resistant paste between the ground lug and the motor
flange. A bad ground can cause intermittent operation also, either by
losing the connection or by causing motor slowdown and increased current
draw, again popping the CB .

Ken H.

> Hello All, I hope everyone's summer is off to a good start.
>
> I did a search here and found several posts dating back to 2012 regardis
> to why a fan blower motor quits working. Mine started acting up yesterday, I
> was driving along with the AC on and the switch in the HIGH position, I
> have a 1975 Royale by Coachmen.
>
> If I leave the switch in the HIGH position I noticed it will work for a
> few minutes then the fan quits, several minutes later the fan comes on and a
> few minutes later it quits again.
>
> Where should I begin trying to locate what might be causing this
> intermittent function?
>
> Thanks,
> Mike
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[mike]

Thanks for the suggestions fellows. I will check for obstructions, I did feel for a loose connection but everything seemed solid. I will clean and
reattach the ground wire as well.

Will the circuit breaker re-set itself because each time the fan stops and starts again I don't need to intervene or re-set?

If it is the fan motor is there a specific part number?

Thanks,
Mike

 

[john r. lebetski]

GM did not uses weatherpak connectors in the 70s. Clean the connections at the hi blower relay and the blower resistor. If baddly corroded replace
them. Not expensive. I use Caig D5 Deoxit on such connections.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[jim kanomata1]

You might want to check the grounding wire as the blower housing is
fiberglass and the screw tends to strip and get loose.

> Instead of a fuse, you probably have a thermal breaker...it heats up,
> opens the circuit..;cools down and closes atarting the fan again. Your fan
> is
> either failing, or something obstructing the fan, it's pretty easy to pull
> the fan and see if it spins freely...otherwise you may have a loose
> connection, causing the wire to heat up. Remember, the high speed fan
> runs only when the alternator is spinning, low and medium run from the
> battery.
> --
> Sean and Stephanie
> 73 Ex-CanyonLands 26' #317 "Oliver"
> Hubler 1-Ton, Quad-Bags, Rear Disc, Reaction Arms, P.Huber TBs, 3.70:1 LSD
> Honda 6500 inverter gen.
>
> Colonial Travelers
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502