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Topic: Cruise Control Disengageing (Read 380 times) previous topic - next topic

Cruise Control Disengageing

I was bouncing along I-10 in southwest New Mexico/southeast Arizona a couple of days ago.  When I went over a particularly large bump the cruise control disengaged.  This happened several times over the next several miles, it was a bit of a nuisance.  I thought there was probably an accelerometer that was getting weak.  As I continued along that mindless stretch of highway I thought about how, even after over 17 years and 100,000 miles in this coach, I really knew nothing about the cruise control system.  Where were the brains of the system, where was an accelerometer and where were all the wires and connections that could chafe or come loose. 

As I continued the problem got worse with the cruise disengaging very often.  I tried turning the cruise off then back on but that made no difference.  I finally gave up on it and drove on without it, figuring I would work on it when I got to a stopping place.  (I am sure many of you have already figured out what was wrong, but not me.)  After a while, out of the corner of my eye, I noticed a couple of red flashes down to my left.  It was the light on the retarder switch.  The retarder joy stick had vibrated back from the off position and would just tickle the number one position with every bounce, disengaging the cruise control. 

Moral of the story:  If your cruise control acts crazy, think first of the retarder. 

For me, I will now try to find out if there is, in fact, an accelerometer in the system and where the brains are located. 

Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
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Re: Cruise Control Disengageing

Reply #1
There in no accelerometer in the system.  The cruise disconnects when the brake lights or disconnect switch on the smart wheel find ground.  Period.  Probably a bad connection at the retarder joy stick?  Start with the simple (and cheapest) stuff first.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: Cruise Control Disengageing

Reply #2
Rich and Jan, it was great seeing you during your stop over at the SKP Ranch. Hope to see you at Q next year. I've had the retarder joy stick pounded one notch on a bad road. Very confusing. I've also not turned it off completely with the same results.
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: Cruise Control Disengageing

Reply #3
A few times I had the cruise keep on disengaging and it was the joy stick not pushed all the way back.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Cruise Control Disengageing

Reply #4
I had a similar problem when the telescoping steering column came up with a thud and dislodged the ground in the column.
Is the horn still functional ?
88 Grand Villa 36' ORED 3208 (throwaway)Cat.
 Build # 3150
Happiness is the maximum agreement of reality and desire.

Re: Cruise Control Disengageing

Reply #5
My situation was purely the position of the joy stick.  Hopefully I will remember that next time my cruise control gives me grief.  And Woody, thanks for the info about no accelerometer. 
Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
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Re: Cruise Control Disengageing

Reply #6
Driving down the highway with joystick not-in-off position usually turns on retarder when throttle pedal is released.  This can be desirable.

But if also driving under cruise control, when retard turns brake lights on, cruise turns off and remains off.

Some have added a handy dash switch to optionally prevent brake lights from turning on when retard is active. 

When driving under cruise control, every dip in the road usually momentarily brings throttle to zero, and at bottom of dip, cruise will increase throttle to maintain set speed.  If retard turn on brake lights, cruise will not start back after dip.