Home » Public Forums » GMCnet » Air compressor electric draw/relay (Inexpensive Dana replacements)
| Air compressor electric draw/relay [message #252309] |
Mon, 16 June 2014 13:58  |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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I am wondering what capacity the stock wiring system has to run an air compressor. The Dana barely functioned when I got this coach (how many amps does that style draw?), and gave up completely not too long after. I got a high volume 12 volt compressor that works fine, but has a 30 amp inline fuse and alligator clips to hook straight to battery. I picked up a little emergency inflator and it says it draws only 8 amps. I am thinking I would have to install a relay from the original pressure sensing switch on the air tank with the higher volume pump, and could probably just install the small pump directly. I couldn't find compressor swap/upgrade/downgrade tutorials on the forum, not sure if using the wrong keywords or what. Thoughts and links are appreciated...
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: Air compressor electric draw/relay [message #252325 is a reply to message #252309] |
Mon, 16 June 2014 16:16  |
Francois
Messages: 161
Registered: October 2012
Location: Southern California
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I did something similar. The wiring harness has a stock 12 gauge brown wire for power, wired to an ignition switch accessories terminal. I went with a 10 gauge (also brown wire) and wired it directly to the battery. If I had kept the stock 100-120 psi airbags, I wouldn't have gone with the 2 inexpensive 2 cylinder compressors I used, but I replaced my airbags with the Sully system, which requires at most 50 pounds. This is an easy job for my inexpensive inflators. It fills up all the way to 44 from 0 in 30 seconds or less. I have had no reliability issues.
I know a lot of guys disagree and swear by the automatic suspension system, but I disconnected mine and ran DOT nylon to the front and have a pressure gauge for each side at the front. Truckers do the same thing. Granted, you don't want to be looking at the gauges and inflating or deflating while driving, but at the beginning, end, stops and even at red lights, I would not consider adjusting the ride unsafe.
It is, to me, a comfort knowing exactly what the suspension is doing, rather than wondering if the automatic system is operating properly.
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| Re: Air compressor electric draw/relay [message #252326 is a reply to message #252309] |
Mon, 16 June 2014 16:44 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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Even with the stock system you should install a fused or breakered feed from the battery to the compressor using a relay controlled by the pressure switch. 10GA wire is good.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: Air compressor electric draw/relay [message #252327 is a reply to message #252309] |
Mon, 16 June 2014 16:46 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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I ran a fused 10 gauge wire from the battery (actually the boost solenoid) to a Bosch type relay that is switched by the pressure switch on the tank. The PO had wired in a toggle switch so the compressor (relay) can be turned off from inside. This runs my compressor without issue. I replaced my Dana compressor, not because it wasn't working properly, but because it sounded like it was going to fly to pieces at any moment. I replaced it with a Viair 350-C:
http://www.gmcmhphotos.com/photos/g5506-new-viair-suspension-compressor.html
I know some people prefer a manual system or a minimally adjustable wireless system, but I like having my system fully operational as designed. It allows me to raise the rear end to full height when negotiating uneven surface streets or pulling in and out of driveways, while giving me the travel height automatically just by the turn of a couple of valve handles.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: [GMCnet] Air compressor electric draw/relay [message #252329 is a reply to message #252328] |
Mon, 16 June 2014 16:50 |
Mr ERFisher
Messages: 7117
Registered: August 2005
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Well here
http://www.gmcws.org/Tech/dsimmons/air_suspension/air-suspension-system.html
Erf
On Monday, June 16, 2014, gene Fisher wrote:
> Read here
>
> Erf
>
> On Monday, June 16, 2014, Tyler > wrote:
>
>> I am wondering what capacity the stock wiring system has to run an air
>> compressor. The Dana barely functioned when I got this coach (how many amps
>> does that style draw?), and gave up completely not too long after. I got
>> a high volume 12 volt compressor that works fine, but has a 30 amp inline
>> fuse and alligator clips to hook straight to battery. I picked up a
>> little emergency inflator and it says it draws only 8 amps. I am thinking I
>> would
>> have to install a relay from the original pressure sensing switch on the
>> air tank with the higher volume pump, and could probably just install the
>> small pump directly. I couldn't find compressor swap/upgrade/downgrade
>> tutorials on the forum, not sure if using the wrong keywords or what.
>> Thoughts
>> and links are appreciated...
>> --
>> 1975 Glenbrook
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://gmcmotorhome.info/
> Alternator Protection Cable
> http://gmcmotorhome.info/APC.html
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Air compressor electric draw/relay [message #252330 is a reply to message #252328] |
Mon, 16 June 2014 17:00 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Mr. Erf, read what? no link provided.
Anyone have an actual amount of air tubing and metal connectors to rebuild Power level system? P.O. butchered mine, and I would like to return to OEM standard. Perhaps with a new compressor, replacing the Dana.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: Air compressor electric draw/relay [message #252333 is a reply to message #252309] |
Mon, 16 June 2014 17:15 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Do you have rear house batteries? Is your compressor mounted inside the coach about 2/3 of the way towards the rear on the driver's side?
Your answer to those two questions will determine the appropriate answer to your questions.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Air compressor electric draw/relay [message #252354 is a reply to message #252326] |
Mon, 16 June 2014 20:20 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
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midlf wrote on Mon, 16 June 2014 15:44Even with the stock system you should install a fused or breakered feed from the battery to the compressor using a relay controlled by the pressure switch. 10GA wire is good.
If you have an EL II system, you should do a simmple mod that feeds the compressors directly from a 12V source and let the dash controls just operate the relays that are already there. The performance is much better. I tells me that even GM didn't get the wire gages down right ! I suspect that the earlier systems had the same problem.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Air compressor electric draw/relay [message #252357 is a reply to message #252333] |
Mon, 16 June 2014 20:34 |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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The replies have been excellent, thanks!
When I got the coach it had the Dana compressor up by the radiator, and a supplementary compressor that had a manual switch in the cockpit. Must have been nice when it was all functioning - Dana ran by pressure switch on tank (also up under the driver side front access door), just kick in the supplementary when you air up from sitting a while. The supplementary pump had burned through itself internally, and was essentially a short when you threw the switch. The Dana rattled its way to death the first few days of camping, then I switched to airing with an emergency style 12 v compressor directly into the air bags with Schrader valves at the connection. I have one house battery in the back by the Onan. Pretty sure I have a PowerLevel system, it has round controls. I would have to add air lines or electric lines, or both, to re-locate the compressor from the front.
Acknowledging that a relay is my preferred end solution, how many amps did an original Dana pull? Comparable to this little compressor I have found that pulls 8 amps? My easiest solution is to use the wiring that is there...
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: Air compressor electric draw/relay [message #252365 is a reply to message #252357] |
Mon, 16 June 2014 21:16 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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I'm not positive, but I think the Dana was fused at 30 amps. That is what I have my real that feeds the Viair fused at. If you have round knobs low on the dash you have Power Level. Those valves are prone to leakage and can be rebuilt, but the best solution is the JR Slaten brass replacement valves: http://appliedgmc.com/prod.itml/icOid/738
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: Air compressor electric draw/relay [message #252370 is a reply to message #252365] |
Tue, 17 June 2014 01:53 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I just checked the wiring diagram. It is a 30 amp CB. Pull 10 ga. wire and and switch it with a relay. Do not forget to use 10 ga. on the ground side also.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Air compressor electric draw/relay [message #252480 is a reply to message #252383] |
Wed, 18 June 2014 11:25 |
glenn2726
Messages: 234
Registered: June 2014
Location: Topeka, Kansas
Karma: 2
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Hi all I am a new member and just found a leak on my leveling system. I have a 74 GMC and the air tank is on the drivers side with upgraded pump. The leak are at the lower outlet of the air tank at a round part with 2 wires going to it. It is leaking around the top. I would guess this is the Air Pressure switch? Any ideas of a part number for this item? The pictures above showing the pump and tank also show the 2 wires going down to this part but that is where the picture was cutoff. Any help on a part number and where to purchase would be a great help..Thanks
Glenn W
Topeka, KS
1974 GMC 26 ft. Color:Camel Interior:Canyon Land
Side Bath, Rear Sitting Area
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| Re: [GMCnet] Air compressor electric draw/relay [message #252483 is a reply to message #252480] |
Wed, 18 June 2014 11:54 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Glenn,
I wouldn't worry at all about getting the "right" part number. Just ask
locally, or via Google, for an "air pressure switch" and select one from
among the many options at many prices. You want one with 80-90 psi cut-on
and 110-120 psi cut-off settings. Many of us use what are really ordinary
air compressor switches which have the advantage of having some
adjustability, but they're not really weatherproof. It sounds as if you
need to stick with a sealed unit. Grainger, eBay, etc., will offer both.
While you're tinkering with the compressor wiring anyway, now would be a
good time to improve the performance and reliability of the compressor by
adding a 10 gauge wire from the firewall 12 VDC supply bolt, through a
circuit breaker and relay, to the compressor motor. Connect the relay's
coil to the new pressure switch.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc.
www.gmcwipersetc.com
On Wed, Jun 18, 2014 at 12:25 PM, Glenn Whitt wrote:
> Hi all I am a new member and just found a leak on my leveling system. I
> have a 74 GMC and the air tank is on the drivers side with upgraded pump.
> The leak are at the lower outlet of the air tank at a round part with 2
> wires going to it. It is leaking around the top. I would guess this is the
> Air Pressure switch? Any ideas of a part number for this item? The
> pictures above showing the pump and tank also show the 2 wires going down
> to this
> part but that is where the picture was cutoff. Any help on a part number
> and where to purchase would be a great help..Thanks
>
>
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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] Air compressor electric draw/relay [message #252485 is a reply to message #252480] |
Wed, 18 June 2014 12:02 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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glenn2726 wrote on Wed, 18 June 2014 09:25Hi all I am a new member and just found a leak on my leveling system. I have a 74 GMC and the air tank is on the drivers side with upgraded pump. The leak are at the lower outlet of the air tank at a round part with 2 wires going to it. It is leaking around the top. I would guess this is the Air Pressure switch? Any ideas of a part number for this item? The pictures above showing the pump and tank also show the 2 wires going down to this part but that is where the picture was cutoff. Any help on a part number and where to purchase would be a great help..Thanks
Call and talk to Jim Bounds at the Cooperative Motor Works: http://www.gmccoop.com/ He helped me with similar problems when I first got my coach. The switch is either the "Low Air" switch or an electric pressure regulator. Either way, Jim will tell you how to fix it and sell you the right part the first time.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: [GMCnet] Air compressor electric draw/relay [message #252489 is a reply to message #252485] |
Wed, 18 June 2014 12:48 |
glenn2726
Messages: 234
Registered: June 2014
Location: Topeka, Kansas
Karma: 2
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Thanks for the replies..the PO had upgraded the system in the past so everything is good, just need to stop the air from leaking...lol... I was just making sure that I had the correct name for the part..and it looks like it will just unscrew from its mount for replacement. I saw on the older systems that it uses higher pressure for inflation of the air bags and right now due to the leak it never shuts off as the air tank never gets over 100 lbs. I will look for the weather proof switch locally and if I can't find one then I will definitely give Jim a holler, thanks for that information. I plan on tackling this before I look for the fuel hose problem...hopefully this will be easier...lol
Glenn W
Topeka, KS
1974 GMC 26 ft. Color:Camel Interior:Canyon Land
Side Bath, Rear Sitting Area
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