Dash Blower inop

T

Tom Katzenberger

Well-known member
Jun 26, 2019
795
287
63
Good evening guys and gals,

My dash environmental controls are inop. I am going to start trouble shooting tomorrow night. I got Ken H's memo on the blower ground and Emery's memo
on the relays. Is there any thing else that is a normal failure item in the HVAC system? I'm looking to address the common items in an attempt to save
time. The coach is a 1977, 23', Birchaven, 455 C.I.D.

Thanks in advance,
Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control, Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
Ignition
 
Keep in mind that the Blower case needs to be grounded, as the blower case
is fiberglass .
Also the 5 pin relay need to have the clips bent to form a solid contact,

> Good evening guys and gals,
>
> My dash environmental controls are inop. I am going to start trouble
> shooting tomorrow night. I got Ken H's memo on the blower ground and
> Emery's memo
> on the relays. Is there any thing else that is a normal failure item in
> the HVAC system? I'm looking to address the common items in an attempt to
> save
> time. The coach is a 1977, 23', Birchaven, 455 C.I.D.
>
> Thanks in advance,
> Tom K.
> --
> Tom & Oki Katzenberger,
> Kingsville, Maryland,
> 1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control,
> Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
> Ignition
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

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

I didn't even think about the case being fiberglass.

Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control, Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
Ignition
 
There are lot of small thing I find out as I worked on them my younger
years.

> Thanks Jim,
>
> I didn't even think about the case being fiberglass.
>
> Tom K.
> --
> Tom & Oki Katzenberger,
> Kingsville, Maryland,
> 1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control,
> Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
> Ignition
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
Good evening guys and gals,

My dash environmental controls are inop. I am going to start trouble
shooting tomorrow night. I got Ken H's memo on the blower ground and Emery's
memo on the relays. Is there any thing else that is a normal failure item in
the HVAC system? I'm looking to address the common items in an attempt to
save time. The coach is a 1977, 23', Birchaven, 455 C.I.D.

Thanks in advance,
Tom K.

******************************
 
Fred,

Thank you so much. I will put this in the front of the inspection list. I do have some spare components from a couple of other coachs I have for
parts.

Thanks again and stay healthy,
Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control, Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
Ignition
 
Don't forget, that relay gets its secondary power from the engine
alternator. Your engine must be running before the fan will run on high
speed. If none of the speeds work, then it can only be the fan ground or
the speed controller in the driver's side of the heater box.
Jim Hupy
Salem, Oregon

> Fred,
>
> Thank you so much. I will put this in the front of the inspection list. I
> do have some spare components from a couple of other coachs I have for
> parts.
>
> Thanks again and stay healthy,
> Tom K.
> --
> Tom & Oki Katzenberger,
> Kingsville, Maryland,
> 1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control,
> Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
> Ignition
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
 
Don't forget, that relay gets its secondary power from the engine alternator. Your engine must be running before the fan will run on high speed. If none of the speeds work, then it can only be the fan ground or the speed controller in the driver's side of the heater box.
Jim Hupy
Salem, Oregon

*****************************
 
Gentelmen,

I have power at the fuse panel and both sides of the heater fuse. I switched blower relays with a known operating blower relay. I by-passed the delay
relay. I have no power at the fan speed selector or the newly switched out relay.

The fan does blow on low when the yellow wire is re-connected on the driver side low speed plug. I disabled the yellow wire in order to have the fan
shut off when the selector is in the off position.

I guess I now know the blower is operating and grounded. I believe the relay is good.

Any additional thoughts and/or ideas are welcome?

I look forward to any suggestions.

Take care,
Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control, Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
Ignition
 
Tom,

I found John Watkins' presentation on HVAC troubleshooting to be a great resource. Here's the link:

https://www.gmcmi.com/wp-content/uploads/2018/04/GMCMH-AC-Control.pdf
The Road Knows…….. Heat/AC Dash Control and Vacuum Controlshttps://www.gmcmi.com/wp-content/uploads/2018/04/GMCMH-AC-Control.pdf
The objective of this session is to…provide a through understanding of the dash Heat/ AC controls and how that knowledge can be used to help in troubleshooting. •To familiarize you with how the factory intended the Heat/AC control systems were
www.gmcmi.com

-Dave
1978 Transmode near Pittsburgh
________________________________
From: tomkatz3
Sent: Thursday, January 20, 2022 7:47 PM
To: gmclist
Subject: [GMCnet] Re: Dash Blower inop

Gentelmen,

I have power at the fuse panel and both sides of the heater fuse. I switched blower relays with a known operating blower relay. I by-passed the delay
relay. I have no power at the fan speed selector or the newly switched out relay.

The fan does blow on low when the yellow wire is re-connected on the driver side low speed plug. I disabled the yellow wire in order to have the fan
shut off when the selector is in the off position.

I guess I now know the blower is operating and grounded. I believe the relay is good.

Any additional thoughts and/or ideas are welcome?

I look forward to any suggestions.

Take care,
Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control, Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
Ignition
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
 
Dave, thanks for posting that link. I was at the seminar, but did not get that handout. It brings together things that are widely dispersed in the
manuals, and will be very helpful.

JohnS
--
John Shutzbaugh, Vacaville, CA, ncserv;
78 Buskirk stretch, "What were we thinking?"
 
Dave,

Thank you. I will continue trouble shooting today.

Take care,
Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control, Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
Ignition
 
Guys,

Thank you all!!

Using all the tools you guys provided, I traced the problem to the A/C Select Switch.

I want to share the solution for others who will travel down this path. Power went into the A/C Select Switch and did not come out when I bypassed the
A/C Select Switch with a pig tail the fan speeds worked beautifully. I pulled the switch and replaced with a switch from a donner coach and all works
great. I will clean and repair the old switch for the next 40 year repair.

Again, I want to thank everyone for all there help and support!!!

Take care and stay healthy!!
Tom K.

--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control, Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
Ignition
 
> Guys,
>
> Thank you all!!
>
> Using all the tools you guys provided, I traced the problem to the A/C Select Switch.
>
> Again, I want to thank everyone for all there help and support!!!
>
> Take care and stay healthy!!
> Tom K.

Tom,

Thank you for closing this out. Often such things happen and we never hear where the problem was let alone how it was cleared.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
Matt,

No worries. It is because of others and there sharing that I am able to more easily repair my coach. The thanks goes to all those who preceded me.

Take care,
Tom K.
--
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control, Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee
Ignition
 
Almost every time I turn that blower on I have to just touch the fuse in the fuse block to make it work. System is only good for defrost anyway, too
many leaks overcome the blower output.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
On Sun, Jan 23, 2022 at 4:32 PM Terry via Gmclist
wrote:

> Almost every time I turn that blower on I have to just touch the fuse in
> the fuse block to make it work. System is only good for defrost anyway, too
> many leaks overcome the blower output.
> --
> Terry Kelpien
>
> ASE Master Technician
>
> 73 Glacier 260
>
> Smithfield, Va.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
Poor connection

>
>
> On Sun, Jan 23, 2022 at 4:32 PM Terry via Gmclist

>
>> Almost every time I turn that blower on I have to just touch the fuse in
>> the fuse block to make it work. System is only good for defrost anyway, too
>> many leaks overcome the blower output.
>> --
>> Terry Kelpien
>>
>> ASE Master Technician
>>
>> 73 Glacier 260
>>
>> Smithfield, Va.
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
>
>
> --
> Jim Kanomata ASE
> Applied/GMC, Newark,CA
> jimk
> http://www.gmcrvparts.com
> 1-800-752-7502
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
Yeah, I know,I already cleaned those holders with a wire brush until they looked shiny, but upon reapplication of power and then time (week later) it
was doing it again. Other fuses are ok now, so maybe it is the firewall connection at the back of the fusebox.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
Try using a little bit of dielectric grease on the ends of the fuse. Don’t use silicone grease. It’s not the same. This should prevent surface corrosion and likely eliminate your problem.

Emery Stora
77 Kingsley
Frederick CO

>
> Yeah, I know,I already cleaned those holders with a wire brush until they looked shiny, but upon reapplication of power and then time (week later) it
> was doing it again. Other fuses are ok now, so maybe it is the firewall connection at the back of the fusebox.
> --
> Terry Kelpien
>
> ASE Master Technician
>
> 73 Glacier 260
>
> Smithfield, Va.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
 
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