Forum Discussion

Canadian_Rainbi's avatar
Canadian_Rainbi
Explorer
Oct 28, 2015

Intermittent Cruise Control SOLVED

Solved. See my latest post.

2002 Itsaca Horizon, Cumming 5.9, Allison 6 speed (M2000?? WAG)

Cruise control drops out intermittently. Few seconds, minutes, or many minutes. Sometimes runs fine for hours. It seems to be most stable on well paved smooth roads. However, hitting a rough patch can't be pointed to as the cause. That a bump won't set it off, but it happens much more frequently on rough roads.

I have tried fiddling with the control lever, can't make it act up.

It is often a problem after start up then settles down.

When we had the Silveleaf working we could see the CC speed being reset downwards.

Sometimes, driving at a steady speed with cruise control off, I take my foot off the throttle to find that it (CC) had engaged at that speed.

As a junior Radio-TV tech in the 60's, I can tell you I HATE intermittent problems! And I know how long it can take to track them down. At $100.0 per hour shop rates I've been putting this off for several years.

Anyone else run into this problem?
Class A
  • Jim's avatar
    Jim
    Explorer
    Dec 01, 2016
    Glad to hear you got it sorted. Cruise control just makes the trip so much more comfortable.

    It was the flyback, wasn't it?
  • Canadian_Rainbi's avatar
    Canadian_Rainbi
    Explorer
    Dec 01, 2016
    SORTED Finally

    Called Freightliner who said probably the stick on the steering column. Gave me the part number which I passed on to my tech who added it to the list of things to be done before we headed south in mid October Like in a week!

    Leaving the shop it wasn't working. En route we had it looked at by a Freighliner shop in Medford. Took them about three hours to sort it. Seems that a GM switch was subbed. Also a module needed to removed from the steering column because it's function was now included in the stick.
  • topflite51's avatar
    topflite51
    Explorer
    Oct 30, 2015
    If all else fails check bulb filaments in turn/brake/tail lights a loose filament can cause intermittent problems with CC.
  • Canadian_Rainbi's avatar
    Canadian_Rainbi
    Explorer
    Oct 29, 2015
    As a lowly apprentice in a 5 tech shop I got to be pretty good at changing out the flybacks in RCA TVs. There was a local hotel that had the same model in every room. Many of the rooms were occupied by long term tenants with less than stellar social skills. I remember one apparently told the desk that his TV didn't work. Half an hour later he called the desk again to say that his TV was on fire!

    I soon learned to diagnose a burned out flyback by the smell.

    I also carried a small scar on the tip of my little finger for decades (It's gone now). It started as a burnt hole, courtesy of a high voltage rectifier. :E
  • Jim's avatar
    Jim
    Explorer
    Oct 28, 2015
    Hah! Three of us here with the same background.

    I think the problem is your 8008 processor.
  • Jagtech's avatar
    Jagtech
    Explorer
    Oct 28, 2015
    From another Radio-TV tech from the 60's, I think its your flyback :B
  • Canadian_Rainbi's avatar
    Canadian_Rainbi
    Explorer
    Oct 28, 2015
    Thanks all for the help and suggestions. Now I know that it is a known issue, though with various solutions, I'll have to take it to a shop, either a Freightliner shop, or to my own tech when we get back home. I'll talk to whoever and make sure that they are aware of the possibilities and make sure that they check the obvious and/pr cheaper fixes first!

    We're on the road, be in Mexico in about a week for the next 5 months or or so. Really can't have it in the shop for long--motels get really expensive, not to mention not having all our stuff. I can live with it the way it is now, if it fails altogether I'll just have to shorten the driving times to avoid the fatigue. Or have DW drive! She drives it a bit at home and has driven in the USA but would not really be comfortable driving in Mexico.

    Thanks Again

    I no longer have the physical ability to do any of this myself.
  • spotrot's avatar
    spotrot
    Explorer
    Oct 28, 2015
    Ssme issue with my Ford chassis. CC wouldn't engage sometimes. Turned out to be switch on brake master cylinder. Easy to test. Cost $15 to fix. Fine since then.
  • Vulcan_Rider's avatar
    Vulcan_Rider
    Explorer
    Oct 28, 2015
    Carvin Marvin wrote:
    Could be the brake switch. Some are adjustable.


    I was going to say that too BUT.....the brake switch will not make it ENGAGE when you had it shut off.
  • fcooper's avatar
    fcooper
    Explorer
    Oct 28, 2015
    Canadian Rainbirds wrote:
    Freightliner chassis (and says Freightliner on the steering wheel, cruise control in on the turn signal lever.


    One known issue with the Freightliner chassis - Cruise Control Problem is the brake light switches (2). They are part of the air brake treadle, and are only accessible from beneath the coach. They are prone to corrosion, and the corrosion can become a conductor that is not sufficient to turn on the brake lights, but is sufficient to turn off the cruise control.

    Look at this two page post on the Freightliner forum on IRV2. It has a lot of good info that may help you.
    Thread-cruise control-IRV2

    If you don't find your solution there, get into the Freightliner forum on IRV2 and do a search on "brake light switch" and you'll find several other threads that may be helpful.

    Good luck and let us know when you find the solution.

    Fred

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