Can?t get sliders to recognize emerg brake

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JoelP

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San Jose, CA
Today when we tried to leave our site in St Mary MT none of the slideouts would come in. Two showed the indication that the emergency brake wasn?t set, but it was. It seems this is the common problem for all 3 slides. I unset and reset it 4 times to no avail. I looked at what seemed to be the mechanical emerg brake switch. When I pressed it it released the levelers, thinking I had turned emerg brakes off, so I believe the switch works. Next I found one relay that said something related to Park and swapped it out with another identical relay, but no benefit.

I cranked the bedroom closed and finally used the manual override to bring in the other slides. The manual override only functions to retract, but I have 16 more days of travel to go and sure could us some ideas of how to fix this. Or at least  way to manually power the slides out.

Thanks in advance.

Joel
 

John From Detroit

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Is this a foot pedal operatred E-Brake? Parking brake, if so then there is a switch on the brake arm assembly. this switch can cause this issue by hanging up. Solution varies  Sometimes I have to release and re-set the brake a few times..

Other times I've Messed with the switch directly

Also there are likely two wires hooked to it. or should be.. Thankfully the tabs are smaller than normal so the odds of hooking up a "Wrong wire" are slim.

If you have other types of brakes. there is still some type of switch.
 

JoelP

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John From Detroit said:
Is this a foot pedal operatred E-Brake? Parking brake, if so then there is a switch on the brake arm assembly. this switch can cause this issue by hanging up. Solution varies  Sometimes I have to release and re-set the brake a few times..

Other times I've Messed with the switch directly

Also there are likely two wires hooked to it. or should be.. Thankfully the tabs are smaller than normal so the odds of hooking up a "Wrong wire" are slim.

If you have other types of brakes. there is still some type of switch.

Hi John,

Thanks for your reply.  That switch was the first place that I looked.  Actually there is only one switch attached to the mecahnism under dash and it has only one wire attached.  I assume that it sees ground from the mount. If there is another switch I sure don't see it. Strangely it is fully extended when the brake is activated and is compressed when it is released.  That means that even with a slight brake compression it releases this switch.  I have a difficult time believing that this is the switch that the sliders are looking at since it doesn't activate upon compression.  Furthermore i am convinced that this switch is working.  I had the rig on levelers and when I pressed this switch it immediately started to retract the levelers.  That says to me that this switch must be working to detect when the parking brake is released.

I called a mobile RV mechanic who looked at this, relays and and more and finally concluded he had no idea of the source of the problem. Tomorrow I am trying an RV/Truck mechanic in Great Falls to see if I can have more luck.  It's not much fun to use an RV where the slides cannot be extended.

BTW the chassis is a Workhorse W22 and the slides are PowerGear.
 

Gary RV_Wizard

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A few ideas or possibilities...just guesswork.
At the slide controller end there is probably something that signals the brake is set as well as any other interlock condition it expects.  Typically the interface is +12v on a wire (or the lack thereof).  You can probably wire a temporary override until you figure out why the emergency brake isn't being detected as it should be.


If the PG controller doesn't have a terminal for the interlock connection sensing, there is probably a relay on the line that supplies +12v power to the controller.  That relay would be controlled by the emergency brake switch. If you can find that, you could override it .


Usually there is also an interlock with the ignition switch and maybe transmission in Park.  The nature of the interlocks have changed over the years, so not sure just what your coach requires.  My '04 required that the ignition be off, but more recent years require it to be on (using engine alternator to assist with power). 
 

JoelP

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Gary RV_Wizard said:
A few ideas or possibilities...just guesswork.
At the slide controller end there is probably something that signals the brake is set as well as any other interlock condition it expects.  Typically the interface is +12v on a wire (or the lack thereof).  You can probably wire a temporary override until you figure out why the emergency brake isn't being detected as it should be.


If the PG controller doesn't have a terminal for the interlock connection sensing, there is probably a relay on the line that supplies +12v power to the controller.  That relay would be controlled by the emergency brake switch. If you can find that, you could override it .


Usually there is also an interlock with the ignition switch and maybe transmission in Park.  The nature of the interlocks have changed over the years, so not sure just what your coach requires.  My '04 required that the ignition be off, but more recent years require it to be on (using engine alternator to assist with power).

Hi Gary,

I was also thinking that there has to be a way to override this at the slide controller, but I am n fear of adding this in the wrong place without the schematic to this controller.  Last night I started to look online for more info on my parking brake system and believe now that the levelers use the simple switch on the parking brake pedal, but the slides use a more sophisticated indicator. I believe I have the J72 parking brake system in my Workhorse  W22 chassis. This is what I found on line:

The J72 system incorporates a unique full-circle parking brake. The automatic electric/hydraulic parking system controls the transmission/propeller shaft mounted parking brake. This system consists of a pump motor relay, vehicle ignition relay, electric/hydraulic pump, reservoir, proportional relief solenoid valve, pressure transducer, and an electronic control module (ECM). The ECM monitors seven inputs from the vehicle and controls the pump motor relay, auto-park light, park brake warning light, buzzer, proportional valve, and pressure transducer.


Since I checked the relay I am thinking it may be the pressure transducer or worse yet the ECM.  This is scary complicated. I wonder if I can even find these parts in Great Falls, MT. if that is what failed. Perhaps the oveerride will be easier to figure out. Do you think that the schamtic for this would be in the Winnebago data sheets?
 

Gary RV_Wizard

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I doubt if the park/emergency brake itself is at fault.  The chassis brake system has no knowledge or built-in function for slide interlocks.  There will be some simple add-on mechanism which the coach (body) manufacturer uses to detect that the brake is on and activate the slide controls. 

Have you looked at the Winnebago schematics available online? Winnie has extensive year/make/model info available.
https://winnebagoind.com/product-resources/product-information

If that doesn't help, call Winnie Customer Service and see if they can tell you how the slide-Park-brake interlock is done.

I had an older W22 than yours, a 2002 under a National Dolphin.  The slide interlock was a simple +12v wire from the Park position on the shifter (PRNDL), but mine only required Park position and did not require the Emergency brake set.
 

JoelP

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I visited a truck repair shop today and they found nothing wrong with the parking brake or the ECM associated with it.

Next I hired a mobile mechanic who tried in vain to trace the wires from the brake to the slide controller.

I tried to download the wiring diagrams, unsuccessfully then called customer care at Winnebaago and, after a brief wait, someone came on to help me.  He struggled to identify the wire that ran from the emergency brake to the controller, but eventually identified a DY wire.  No such wire label existed at the controller and he had no diagrams showing what was hooked up to the controller or the control panel.  In doing all of this he told me that every wire has a part number stamped on it to identify its purpose.  My mobile mechanic and I had identified the wires that came from the control panel to the controller power and logic.  I noticed that one wire of eight was white and the others were yellow, so I read that wire's part number to the Winnebago guy, who was able to identify this wire as one going to the "master slide lock".


Initially I had no idea of what that might be and then he said, "it's often is a switch with a key.  Of course!!! That is the common point for all of the slider controls.  Sure enough I went to look at the switch that I never touch and found the key slightly out of unlock position.  I turned it to the full unlock position and all is now well!


So what did I learn from this? 


1. Occum's Razor tells us that the simplest thing is generally the thing that prevails.
2. Just because the control panel says that the parking brake is not engaged that doesn't necessarily mean that it is the parking brake interlock to blame.
3.  I need to take that master slide lock key out of that master slide lock switch and hang it where it won't get me in trouble any more.
4.  Thanks to Gary's reminder about Winnebago customer service I was able to tap that resource.  I had my doubts about then for awhile, but in the end they solved my problem for me.


Perhaps someone else can benefit from my stupidity to save themselves a couple days of stress.


 

Larry N.

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Great -- glad you got it solved. And thanks for coming back and letting us know the solution -- that's one that's not likely in anyone's bag of tricks.
 

ChasA

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I once turned that key accidentally.  But fortunately I remembered seeing it and quickly solved my problem .
 

Old_Crow

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Tom's Place, California
That makes me glad that on my coach that key switch is also the switch that runs the slide in and out.  I have enough problems remembering to set the parking brake, much less having to worry about another switch.
 
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