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HWH vacuum solenoid harness installation

July 20, 2024, 01:40:58 pm

While in TX having Keith R. replace my slide bladders, he mentioned this harness that FT now uses with the slide rooms.  It causes the vacuum solenoid to stay running any time the slide movement key is on, rather than timing out or stopping once a certain amount of vacuum has been attained.  I got one for each room, but haven't figured out exactly what connections I'm making.

Currently there are 3 2-pin connectors that go to each room bladder block.  Vacuum (solenoid), vacuum pressure sensor and air seal.  This new adapter is a y-adapter.  The block diagram even mentions that the OEM may tee these both together, and it looks like they mean the vacuum and air bladder solenoids.  Are those the two that should be connected to each side of the Y?  And then does the input connect to the air seal connector on the coach?

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Re: HWH vacuum solenoid harness installation

Reply #1 – July 20, 2024, 03:08:11 pm

I am interested in this modification. I'm guessing that the idea is to allow the switch to make to operate the indicator light and allow the room to move while continuing to pull vacuum on the bladder. The air compressor will love this! Be sure not to leave this on too long. I have fitted vacuum/pressure gauges on my slides so I could confirm operation. I will be seeking more information on this kit. Sorry I can't actually tell you how to connect this yet. You may need to do some wiring mod.

https://1drv.ms/i/s!AqaEiIhKCAKbkrp4mDIknaQ35V8d1w?e=q1aQxL

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Re: HWH vacuum solenoid harness installation

Reply #2 – July 20, 2024, 04:46:27 pm

Did you get this part from FOT?  What is it called and part #.  I just had my bladder replaced by Keith last week and he didn't mention this.

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Re: HWH vacuum solenoid harness installation

Reply #3 – July 20, 2024, 10:33:13 pm

Keith offered it to my when he did my slide bladders in May.  I declined at the time, but now decided I want them.  As my system is now, when you turn the key on, the yellow light flashes as the bladder deflates, then the vacuum solenoid pulls a vacuum on the bladder.  As I understand it, once a certain amount of vacuum is reached (from my gauges, it looks to be 20in-Hg), the vacuum solenoid closes, stops creating vacuum and the light goes solid.  When you press the button to move the room, the vacuum solenoid engages again, to keep the bladder under vacuum while the room is moving.

The new wiring is supposed to keep the vacuum on, even after it's achieved it's max vacuum, until the key is turned back to the off position.  I suppose this ensures the bladder is always pulled back as far as possible from the room.

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Re: HWH vacuum solenoid harness installation

Reply #4 – July 21, 2024, 10:06:25 pm

That's interesting. Just for informational purposes I tried this. Turn the key on to a living room slide. Went outside to listen to the pump. Never shut off. Went back inside and the amber light was solid. Went back outside for a few minutes and the pump never quit. My thought is the vacuum switch turns the amber light solid but the pump keeps running until the key is turned off. Then it runs until the pressure switch is made upon inflation. It could be a year model difference.

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Re: HWH vacuum solenoid harness installation

Reply #5 – July 22, 2024, 01:31:33 am

I spoke with Keith today and verified that the one input is from the slide bladder output of the system.  The two outputs go to the slide bladder solenoid and vacuum solenoid.  The stock vacuum solenoid output from the system is left disconnected.

When you turn the key, it energizes the bladder solenoid and closes the inlet pressure, and also now turns on the vacuum generator.  As long as the key is on, this happens.  The light goes solid after about 20 seconds, when my pressure switch shows it's preset value.  Based on my gauges, it looks to be roughly 20in-Hg.

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Re: HWH vacuum solenoid harness installation

Reply #6 – July 22, 2024, 10:54:39 am

Keith, is this cable as simple as a Y cable with Ford type connectors?

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Re: HWH vacuum solenoid harness installation

Reply #7 – July 22, 2024, 10:59:30 am

They are weatherpack connectors, yes.

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Re: HWH vacuum solenoid harness installation

Reply #8 – July 22, 2024, 01:12:18 pm

2 connector like this would do it?

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Re: HWH vacuum solenoid harness installation

Reply #9 – July 22, 2024, 02:51:10 pm

The units Keith sold me are one male and two females...the opposite of what you listed.

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Re: HWH vacuum solenoid harness installation

Reply #10 – July 22, 2024, 04:36:01 pm

My vacuum switches satisfy around 10" vacuum. Having just dome some work to stop water leakage on one my slides I spent a lot of time observing operation. Watching the bladders you can see them sucked and then when the vacuum stops they expand slightly. For my leaker the problem was the center of the slide out box was bowing down so the bladder couldn't reach it. Turning up the bladder pressure seemed to push sides of the box top down further making the leak worse. Fix was to adjust the 2 brackets that pull the front of the slide box up when it is open. I removed the angle brackets mounted on the wall and slotted the mounting holes to raise them about 3/16". As the slide opens you can see the roof center get raised and this is leaving a near perfect 1/8" gap between the bladder and slide before it is inflated. Passed the dump 5-gallon pail of water of the slide top open test.

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Re: HWH vacuum solenoid harness installation

Reply #11 – July 22, 2024, 09:30:03 pm

When I replaced the bladder for the bedroom slide in 2015, i couldn't get the bladder to collapse enough to get the room back into the hole. I did it in my yard in Florida in the summer time. Rains nearly every day. Called HWH and first was told it would be several weeks before I could talk to anyone. I told them that was unacceptable, and explained the situation. They got someone right away and he told me how to trick it so that the vacuum would continue to run and I was able to get the room back in the hole. They sent me the harness that you described and I installed it. Worked perfectly. When I replaced the bladder on the main slide a few months later, I made my own harness. I don't remember what HWH charged but it was a lot for what it was.

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Re: HWH vacuum solenoid harness installation

Reply #12 – July 23, 2024, 09:19:35 am

Quote from: DaBus – July 22, 2024, 01:12:18 pm

2 connector like this would do it?

A couple of years ago Keith told me about this connector when he was at mot and replacing my slide seal. I bought 2 for around 15 bucks each I think, Keith installed them, one he had hands on while changing the vacuum block with the new slide seal and the other was right there 3 connectors.. got my bill and MOT  charged me $145 (1 hour labor at the time) to install it. Both took him 5 minutes to install, I watched him do it.....  not happy with mot on that one!!

My point is if you want the right part you can get it from mot or probably fot and easily install it your self. Don't try to Jerry rig the wrong part in and complain about problems later....

Keith

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