12 Volt Air Compressor Switch

Topic: 12 Volt Air Compressor Switch (Read 966 times) previous topic - next topic

12 Volt Air Compressor Switch

January 24, 2014, 10:32:53 am

What is the function of the switch located on this air compressor? I operated it and could not tell what it was for. It looks like it is OEM. I did not trace the wiring yet, as I hope you guys could enlighten me first.

Re: 12 Volt Air Compressor Switch

Reply #1 – January 24, 2014, 10:40:07 am

On my U280, it just turns off the power.

Re: 12 Volt Air Compressor Switch

Reply #2 – January 24, 2014, 10:49:57 am

The switch is in the off position (down). I turned it on (up) and could not tell anything happened. I don't think it is a power for the compressor as it runs with the switch off.

Re: 12 Volt Air Compressor Switch

Reply #3 – January 24, 2014, 10:53:58 am

Oh great, now i need to check mine.. lol

Re: 12 Volt Air Compressor Switch

Reply #4 – January 24, 2014, 10:54:34 am

Quote from: Old Hippie – January 24, 2014, 10:32:53 am

What is the function of the switch located on this air compressor? I operated it and could not tell what it was for. It looks like it is OEM.

Which aux compressor do you have? There is some difference between years. I don't recall seeing a switch on our '03's TA-4101-DC...

Re: 12 Volt Air Compressor Switch

Reply #5 – January 24, 2014, 11:00:56 am

Odd. Several of us have added switches in line with the fuse in order to turn off the compressor. My 2002 didn't have any switches there until I did that. Maybe you could post a picture?

Re: 12 Volt Air Compressor Switch

Reply #6 – January 24, 2014, 11:37:42 am

I've got an added switch in the bay that is in the inline fuse circuit. Someday I will move it to the dash somewhere.

This circuit is apparently activated by low pressure in the aux tank that supplies seals, awning etc on our coach.

I've seen another 2002 with the compressor running and that fuse pulled. When they turned off the leveling system the compressor stopped. Apparently there is more than one thing that will activate the compressor relay.

Re: 12 Volt Air Compressor Switch

Reply #7 – January 24, 2014, 12:10:01 pm

After the replies, I went out and looked at the switch again. You guys are correct, it is an on/off switch for the compressor. When I checked it before I guess the pressure was high and that is why the switch did nothing so I left the switch off. Today, the pressure was down and when I activated the switch the compressor came on.
thanks!

Re: 12 Volt Air Compressor Switch

Reply #8 – January 24, 2014, 09:54:24 pm

Don't have a switch on mine. I have always figured that if the compressor turns on I must need air somewhere.

Re: 12 Volt Air Compressor Switch

Reply #9 – January 25, 2014, 09:01:18 am

I had to install the switch on mine. Comes in handy and don't have to pull the fuse if I do not want the compressor to come on. Turn off when I put in storage so if an air leak does occur it will not come on and maybe run forever. DAN

Re: 12 Volt Air Compressor Switch

Reply #10 – January 25, 2014, 12:18:56 pm

Mine, like others I know, used to come on and seem to "stick" on at times. I would find it running and have no idea how long it had been that way. I think it had to do with the pressure valve, maybe a fleck of something preventing it from doing its job. The tech at RnR told me it checked out fine, and it was his suggestion to add a switch (like he had done with several others in the shop) so I could just turn it off if/when I needed to worry about it. Easier than pulling the fuse each time. Since installing the switch, however, it NEVER has "stuck" on. Figures. But it is easy enough to add the switch inline with the fuse.

Re: 12 Volt Air Compressor Switch

Reply #11 – January 25, 2014, 03:51:52 pm

What exactly does that compressor supply air to other than our Zip Dee Awning and leveling?

Re: 12 Volt Air Compressor Switch

Reply #12 – January 25, 2014, 04:06:14 pm

I think it keeps the tanks filled so the air stays up for the step and slides. DAN

Re: 12 Volt Air Compressor Switch

Reply #13 – January 26, 2014, 09:52:18 am

Quote from: Carol & Scott – January 25, 2014, 03:51:52 pm

What exactly does that compressor supply air to other than our Zip Dee Awning and leveling?

It provides air for leveling and keeping the slide bladders inflated. It also keeps a small amount of air in the tanks so that it always has some air. I turn mine off in the garage as the bladders only keep out dust and dirt as no rain will hit it and I turn my leveling off so that is not needed.

Re: 12 Volt Air Compressor Switch

Reply #14 – February 17, 2014, 01:55:30 pm

Added an inline on/off switch in the fuse line today. The aux comp. was cycling 2 to 3 times a day for approx 2 to 3 mins. each cycle. I previously added another compressor for our Zip Dee awning that required 110 psi. The Aux Comp. does not have the psi required to adequately operate the awning. So the aux comp. air lines from the manifold are going to the leveling system and the slide bladders. We are parked on a level surface so I dumped the air from the HWH auto leveling system and turned it off. I presume that there is a check valve for the air bladders somewhere that will keep air pressure in the bladder system. Does any one know where this check valve might located and how ling I could/should expect the slide air bladders to remain inflated. I would like to check it for air loss.

On another note I have read that the aux compressor does keep air in the main tanks and mine show 95psi front and rear so I presume that the aux comp is feeding them. I expect these tanks will lose air pressure while the aux comp is off. I am wondering where the air line is that feeds the main air tanks comes from as I only see 3 coming out of the aux com[ manifold.

Any input from you wise and knowledgeable ones would be appreciated.

Re: 12 Volt Air Compressor Switch

Reply #15 – February 17, 2014, 02:26:06 pm

Quote from: Carol & Scott – February 17, 2014, 01:55:30 pm

On another note I have read that the aux compressor does keep air in the main tanks and mine show 95psi front and rear so I presume that the aux comp is feeding them. I expect these tanks will lose air pressure while the aux comp is off.

On our '03, there is a switch (labeled "Air Tank") next to the driver's elbow. It enables a solenoid to connect the aux compressor to the coach tanks if you need to add air outside of the normal leveling operation. You don't really want to leave it on; it's primarily there to be used as a courtesy if you are getting ready to leave so you don't have to fire up the main engine and disturb your neighbors while you "air up". I think there is also a check valve in this set up; vaguely recalling some portion of this failed in our coach in 2011 and the switch wasn't isolating the aux compressor from the main tanks. Easy to check - Steve monitored the tank pressures on the Driver Info Center when the aux compressor was running and saw they always increased, regardless of switch position.

I believe the protection valves on the tanks are supposed to prevent the tank pressures from falling below 60 psi without an active air supply.

Re: 12 Volt Air Compressor Switch

Reply #16 – February 17, 2014, 02:39:37 pm

Thanks Michelle -

We have the Rocker switch labeled "Air Tank" as well. I have never turned it on as whenever we have started the coach we have had 90/95 psi in the front and rear tanks so the wait is very short before we get up to travel psi. We typically follow the Roland mode of travel and get under way at the crack of 10 +/-.

Re: 60 psi min - Is there a reason for this minimum psi in the tanks?

Re: 12 Volt Air Compressor Switch

Reply #17 – February 17, 2014, 03:18:44 pm

Quote from: Carol & Scott – February 17, 2014, 02:39:37 pm

Thanks Michelle -

We have the Rocker switch labeled "Air Tank" as well. I have never turned it on as whenever we have started the coach we have had 90/95 psi in the front and rear tanks so the wait is very short before we get up to travel psi. We typically follow the Roland mode of travel and get under way at the crack of 10 +/-.

Re: 60 psi min - Is there a reason for this minimum psi in the tanks?

No minimum maintained here on my coach. My tank indicators routinely fall to zero after sitting "a while", even with the compressor left "on". It just comes on at various times to maintain the level system (and possibly the bladder?). If I remember (almost never), I press the switch to let the compressor fill the tanks when I get ready to move it.

Re: 12 Volt Air Compressor Switch

Reply #18 – February 17, 2014, 03:29:16 pm

Quote from: Carol & Scott – February 17, 2014, 02:39:37 pm

Re: 60 psi min - Is there a reason for this minimum psi in the tanks?

I don't know the details of why 60 is the magic number, but the "protection" aspect is to cut off air supply to non-braking entities. It's to ensure you have brakes (especially if something else happened to be leaking).

If your tanks are going down to 0 doing nothing, my guess is you might think about replacing the protection valves and doing a little leak checking (following frame blocking, wheel chocking, etc. for safety when working under and on the air system).

Re: 12 Volt Air Compressor Switch

Reply #19 – February 17, 2014, 04:49:28 pm

The air pressure on our 1997 U295 coach regularly goes to 0 after several days. The air suspension system maintains pressure even when the gauges go to 0. The 12VDC compressor on our coach will not put air into the brake system.

The parking brakes are activated by springs. My understanding is that it takes more the 70 psi in the brake system to fully and reliably disengage the parking brake.

FOT replaced several regulators and check valves a year ago to fix some leaks and put the air system in proper working order. The system maintains pressure much better than before, but still goes to 0 after several days. I consider that to be normal.

Re: 12 Volt Air Compressor Switch

Reply #20 – February 17, 2014, 05:30:33 pm

Quote from: J. D. Stevens – February 17, 2014, 04:49:28 pm

The system maintains pressure much better than before, but still goes to 0 after several days. I consider that to be normal.

Yup.

Re: 12 Volt Air Compressor Switch

Reply #21 – February 18, 2014, 07:18:18 pm

We did not use our coach for 45 days. When I started the engine, the dash air pressure gauges were at 0.
Larry

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