found a surprise in the heater/ac core ....

davidlive

davidlive

Member
Nov 19, 2011
216
27
18
Simi Valley, California
So today i went to find out why the a/c or heater fan wasn't working, first found a blown fuse, with the previous owner running a wire to a switch
then out to broken off bumper lights, removed all that and found i'll have to replace the dash as it's breaking. but back to the dash fan, replaced
the fuse and went outside to check the fan and measure if the voltage is getting there only too smell burning and see smoke coming out of the fresh
air intake, so i figured bad fan motor, and i removed it to find my SURPRISE a rat nest full of rat crap and ugh disgusting stuff.

I still need to check the replace vacuum lines and check or replace valves

Any Suggestions at getting rid of the old rotten rat crap/piss smell ?
So has anyone made a screen / filter for the fresh air ?
is there a better motor that might pull more air ?
(i have a motor from my parts coach i plan to use)

Thanks David
--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
Yes, most folks install a 1/4" hardware-cloth screen over the intake to the
AC.

There is an electric preheater element in the bottom of the blower box,
which can causes vermin nest to smolder, as you have discovered.

The only way to remove the smell is to disassemble and clean,
unfortunately. Ask me how I know.

It's not the blower, but all the sharp turns and corrugated ducting that
slows the air down. GM just wasn't good at AC design for the coach,
particularly for the '73 and '74 models, and the only real solution is a
redesigned blower box and air path, or an underdash supplemental
evaporator/blower.

If you are replacing the dash with one of your own design, find Ken
Henderson's photo essay of the dash he made for his coach, and what he did
to improve the AC air flow.

Rick "who uses fans and wind wings, or the genset and the roof air if
necessary" Denney

> So today i went to find out why the a/c or heater fan wasn't working,
> first found a blown fuse, with the previous owner running a wire to a switch
> then out to broken off bumper lights, removed all that and found i'll have
> to replace the dash as it's breaking. but back to the dash fan, replaced
> the fuse and went outside to check the fan and measure if the voltage is
> getting there only too smell burning and see smoke coming out of the fresh
> air intake, so i figured bad fan motor, and i removed it to find my
> SURPRISE a rat nest full of rat crap and ugh disgusting stuff.
>
> I still need to check the replace vacuum lines and check or replace valves
>
> Any Suggestions at getting rid of the old rotten rat crap/piss smell ?
> So has anyone made a screen / filter for the fresh air ?
> is there a better motor that might pull more air ?
> (i have a motor from my parts coach i plan to use)
>
> Thanks David
> --
> 78 Royal #749
> 74 #136
> Oversteer is when you hit the wall with the rear of the car, understeer is
> when you hit the wall with the front of the car. Hp is how fast you hit the
> wall, and torque is how far you take the wall with you when you hit it.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
 
Amway had a product called "Pet Spray) I think that came in a small pump bottle and was not cheap...BUT IT WORKED, and left no residual stain or odor.
I found it was great at removing most odors from dog crap to decomp and other things in between, like beer-scented automobile carpets. I lost the
Amway guy 20 years ago, don't know if they are still around, but the product was better than FeBreeze at REMOVING odors, not just covering them up to
fool your senses.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
> ...There is an electric preheater element in the bottom of the blower box...

The only thing in the blower box that resembles an electric heater element is the resistor pack that controls the fan motor speed.

The smoke smell was almost certainly caused by the motor burning up because it couldn't turn.

The lowest impact changes to the dash heater/AC system can be found here:

http://www.gmcws.org/Tech/air_conditioning/air_conditing.html
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Every day I become more convinced that I am the only person left on the planet that recognizes nonsense for what it is."
 
The blower resistor is what I meant--old memories needing refreshing.

There is a reason it's inside the blower box (it gets hot), and it's right
at the bottom where nests can be made. It's behind the evaporator coil, and
so hard to get to from the blower opening, but mice can get in from inside
the coach. But they have caused problems like this--I remember from an old
conversation a decade or so back. Probably shouldn't have mentioned it at
all without checking my memory.

Rick "out of practice" Denney

> > ...There is an electric preheater element in the bottom of the blower
> box...
>
> The only thing in the blower box that resembles an electric heater element
> is the resistor pack that controls the fan motor speed.
>
> The smoke smell was almost certainly caused by the motor burning up
> because it couldn't turn.
>
> The lowest impact changes to the dash heater/AC system can be found here:
>
> http://www.gmcws.org/Tech/air_conditioning/air_conditing.html
> --
> 73 23' Sequoia 4 Sale
> 73 23' CanyonLands Parts Unit 4 Sale
> Upper Alabama
> "Every day I become more convinced that I am the only person left on the
> planet that recognizes nonsense for what it is."
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
 
Everyone with a GMC should remove the front panel from the HVAC box at
least once. Doing so will give a much-enhanced understanding of the
working (and non-working) of the system. It also affords the opportunity
to clean out collected debris, dirt, and miscellaneous contaminants (such
as squirrel & mouse nests) which steal away cooling which can't be spared.
Removing the blower dropping resistors from the lower left (driver's) side
of the box is also important because that favorite area for contamination
is only accessible through that little hole. A reduced-size vacuum hose
attachment is needed to clean the area well.

Just take a look at the following photo and some of those before and after
to get an idea of the complexity of the system:
http://www.gmcmhphotos.com/photos/dash-air-conditioning-redesign/p30764-slide141.html

Before you start, download this wonderful guide to GMC A/C; doing the
recommended repairs and modifications is very much worthwhile:
http://gmcws.org/Tech/air_conditioning/air_conditing.html

Ken H.

> The blower resistor is what I meant--old memories needing refreshing.
>
> There is a reason it's inside the blower box (it gets hot), and it's right
> at the bottom where nests can be made. It's behind the evaporator coil, and
> so hard to get to from the blower opening, but mice can get in from inside
> the coach. But they have caused problems like this--I remember from an old
> conversation a decade or so back. Probably shouldn't have mentioned it at
> all without checking my memory.
>
> Rick "out of practice" Denney
>
>
 
Thanks to everyone for the advice, yeah it wasn't hard to get that front cover off, and it's all mostly cleaned out, i just need to head up to the
foam store to replace the foam in it, any thoughts what type to ask for ?

Thanks David
--
78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the
wall, and torque is how far you take the wall with you when you hit it.
 
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