Try googling the problem. You'll be surprised what solutions will pop up. I had the same issue, not on my tractor, but on my 2005 dodge ram diesel pickup. Cruise control would come on and off all by itself. It would speed up, shut off unexpectedly and it made my pickup undrivable. After doing some research on the internet, I came to a link that suggested that I remove all aftermarket bulbs (which I did have), and replace them with factory. I don't know what bulbs have to do with my cruise control, but none the less, I figure it's cheaper than going to the repair shop, and if it didn't work, at least I wouldn't have to worry about bulbs burning out anytime soon. So I replaced all the bulbs to factory......and voila!!!....no more cruise control problems. I know...big difference between tractor and pickup, but try google. It helped me out and saved me a lot of money.
Interesting solution. If I had not already replaced all the lights with their LED equivalents I would give this more consideration. Problem existed before I changed the lights. It was doing this when I bought the truck just not as often ( mainly during/after a rain or truck wash ) I agree that google can be your friend and I did try to research it there before posting it here. I got a lot on links that brought me back to this forum but didn't pan out to be the solution I needed.
I h I had the same issue, only happened when it rained. According to the article that I read, your brake lights are link to your cruise control, that's why whenever you hit the brakes, it shuts off. Installing aftermarket bulbs, where connections may not fit right, or sends wrong voltage can affect your cruise control. If moisture gets into the connection, it can affect it as well. So maybe check the gasket around your brake lights or loose connections maybe the issue. I'm no mechanic, just basing it on personal experience.
Ok, got it into the shop today and replaced the sensor and sensor harness. Liked to choked at the cost ( $129.00 for the sensor and $64.00 for harness ) The old sensor looked ok but the harness has been oil soaked for so long that it was "rubbery". While there did seem to be a minor improvement at first, it soon became apparent that the problem still persists. Next step I'm going to try is having the whole harness from the sensor traced and see if they can find a break or short. Will keep the forum updated as I go.
If it still does it at idle (increases in rpm) when at a shop with insite, have them monitor the set/resume and on/off cruise switches, if it blinks increase when its acting up that will confirm a wiring issue between dash switch and ecm as northern mechanic said. most likely the connection at the firewall to ecm is where I have found them. also check for any sign of moisture in the connections at the ecm.
just so yall think I haven't forgotten. still working on the problem, mechanic thinks he may have it narrowed down to a clutch sensor. going to test that out next time I can get it in the shop. I have set the max cruise speed to 63 which helps prevent the tend to go full throttle. now it runs up to the upper set speed and holds that. not a fix but is a work around until we can figure out the problem. Kwcam, thanks for the input. ill past your suggestions along the mechanic for follow up.
update: still no joy in mudville. KW wants to get it in and start tracing wires and senors. they think its going to be one or the other but can't say how long it will take to " find " the problem. at $100.00 an hr I'm not too keen on them going on a witch hunt until they find it. a couple of hours sure but beyond that is just pissing away money to me. what I have done in the mean time is set the max cruise to 68 mph. turn it on, hit the switch and it goes to that speed and holds. not a fix in any since of the word but does let me have cruise on the highway in 65-70 mph states. once I find a shop that actually wants to work with me to find the problem or I simply start replacing senors until I find the right, I guess i'll have to live with as is.
Rig up a temporary led that lights when you hit resume. You'll see if you're getting voltage into that circuit. That will at least give you an idea as to whether you need to chase wires. Another option is swapping in a test ecm to see if the problem goes away.
