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| Re: [GMCnet] Air Compressor - Continued [message #59727 is a reply to message #59719] |
Sun, 11 October 2009 10:58   |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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Senior Member |
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| Trey Shannon wrote on Sun, 11 October 2009 08:13 |
Moby is a 73 - 26' - Compressor mounted under the driver position - Appears
to be a stock installation
Is there a low current pressure sensor switch or does the switch control
full load ?
Where is the easiest place to install a cut-off switch ?
Thanks..
Trey
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Original system was for the pressure switch to control the full 12 volt motor current, in the range of 20 amps. Many have changed that to a relay system, so the pressure switch only controls the coil of the relay, and the relay gets full current from some place like the battery isolator (fused of course). In the original, the full current went through the ignition switch, and all the underdash wiring. If you were installing a relay system, the cut off switch would be located on the coil side of the relay, between the pressure switch and the relay coil.
Rob Allen
former owner of '76 x-PB
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| Re: [GMCnet] Air Compressor - Continued [message #59730 is a reply to message #59719] |
Sun, 11 October 2009 11:11 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| Trey Shannon wrote on Sun, 11 October 2009 11:13 |
Moby is a 73 - 26' - Compressor mounted under the driver position - Appears
to be a stock installation
Is there a low current pressure sensor switch or does the switch control
full load ?
Where is the easiest place to install a cut-off switch ?
Thanks..
Trey
|
Trey,
We first off have a minor semantic problem here. (Didn't we just do one of these?)
By best place to install a switch, do you mean where to interfere with the vehicle wiring or where to physically mount the switch?
In my '73 23', the compressor is supplied by a breaker that is in the panel behind the glove box. If I were doing as you propose, I would unplug that breaker and add such wiring between that and the original to accomplish what is needed.
On my coach (pretty sure is OE there) the pressure switch supplies the DC to the compressor directly.
If I wanted an easily accessible switch, I would drill a hole in the Power Level panel between the controls and put a lighted switch right there and wire it so it is illuminated when the air pump is disabled.
The compressor can draw a pretty good amount of power for a significant period of time, so be sure the wire you pull is good for it too. Something like 10awg is a good start.
Before you get too far, get some bubbly leak finder and locate the leaks in the system. I can ignore my coach for most of the winter and the compressor doesn't start when I finally pay it some attention.
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
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| Re: [GMCnet] Air Compressor - Continued [message #59745 is a reply to message #59730] |
Sun, 11 October 2009 12:39 |
tmaki
Messages: 200
Registered: September 2005
Karma: 0
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Senior Member |
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Matt Colie wrote:
>
> Trey Shannon wrote on Sun, 11 October 2009 11:13
>> Where is the easiest place to install a cut-off switch ?
>
> If I wanted an easily accessible switch, I would drill a hole in the Power Level
> panel between the controls and put a lighted switch right there and wire it so it is
> illuminated when the air pump is disabled.
I did basically that. DPDT bat handle switch in the middle
of the panel, a 40-amp relay next to it, 30-amp fuse in
compressor hot line, and two LEDs. Green for when the
compressor is operating normally, red for when I switch it
to run without turning the ignition key. Sometimes I want
the system functional and not have to mess with the key.
Center position of switch is completely OFF. Sometimes when
it's hard to hear the compressor, the LED is a nice
indication that at least some part of the system is working.
Red LED reminds that the system is ON even if the compressor
is not running.
A little redundancy, and a little extra wiring. One side
from the constant hot side of the fuse panel, one side from
the IGN side.
No strain, no pain, no drain.
Toby Maki
'73 Glacier 230
Riverside, CA
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| Re: [GMCnet] Air Compressor - Continued [message #59883 is a reply to message #59730] |
Mon, 12 October 2009 13:38 |
jw mills
Messages: 199
Registered: September 2006
Karma: -30
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Senior Member |
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I converted my system. The original power for the compressor now goes
through the pressure switch and operates a 30 amp relay. Compressor
power now comes off the isolator through a 30 amp fuse through the relay
(mounted by the pressure switch) to the compressor. If I don't want the
compressor to run I just unplug the relay removing power from the
compressor.
--
Jim Mills
Greeley, CO
1973 CanyonLands 260 TZE-063V100731(under renovation)
1973 Glacier 230 TZE-033V101993
On Sun, 2009-10-11 at 11:12 -0500, Matt Colie wrote:
> Trey,
> We first off have a minor semantic problem here. (Didn't we just do one of these?)
> By best place to install a switch, do you mean where to interfere with the vehicle wiring or where to physically mount the switch?
> In my '73 23', the compressor is supplied by a breaker that is in the panel behind the glove box. If I were doing as you propose, I would unplug that breaker and add such wiring between that and the original to accomplish what is needed.
> On my coach (pretty sure is OE there) the pressure switch supplies the DC to the compressor directly.
> If I wanted an easily accessible switch, I would drill a hole in the Power Level panel between the controls and put a lighted switch right there and wire it so it is illuminated when the air pump is disabled.
> The compressor can draw a pretty good amount of power for a significant period of time, so be sure the wire you pull is good for it too. Something like 10awg is a good start.
> Before you get too far, get some bubbly leak finder and locate the leaks in the system. I can ignore my coach for most of the winter and the compressor doesn't start when I finally pay it some attention.
>
> Matt
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