Re: Cruise Control Won't Reply #1 – April 10, 2018, 11:46:31 pm Start with fuses. Is there engine vacuum at the cruise control vacuum servo( with throttle cable). Is the cruise control trying but not suceeding( working at 25-30 but not at 60)? The rubber parts on servo eventually fail. My 1986-7 K25 Suburban 350 carburated had the valve rubbers fail to seal. I replaced the entire vacuum servo. Valve rubbers were a GM part at one time. My K5 Blazer/Jimmy Diesel had human interface cable failure. The brains are behind the removable knee panel. I recall a common, on, resume/accelerate, set/coast 22 gauge wires inside a black cover. Unplug the cable from the brain box. Test all wires with a multi meter pressing the buttons for each function. An broken function loop requires the turn signal lever with the cruise control switches and cable be replaced. I found the lever as an after market part. If replacing, tie a sturdy waxed cord to the wire cable. Wrap some electrical tape around the knot area, to help the knot slide past all of the turn signal wires in the steering column. Pull the wires up the steering column leaving the waxed cord as a fish wire at the lever hole. The lever is held in with a spring detent. Pull it out. Tie the new lever wire cable to the string, wrap with electrical tape and pull the new cable back in. Snap new lever into turn switch socket. Plug the new wire cable into the brain box. Whew, lot of words for a simple task!The K5 diesel also had a vacuum pump failure. 1 Likes
Re: Cruise Control Won't Reply #4 – April 11, 2018, 07:20:56 pm a better description of what it does, or won't do would be helpful. If you still have incandescent brake light bulbs, I've heard that a burned out bulb will prevent the cruise control from coming on. Easy to check, and inexpensive to try. RonB
Re: Cruise Control Won't Reply #5 – April 11, 2018, 08:17:32 pm Quote from: RonB - April 11, 2018, 07:20:56 pma better description of what it does, or won't do would be helpful. If you still have incandescent brake light bulbs, I've heard that a burned out bulb will prevent the cruise control from coming on. Easy to check, and inexpensive to try. RonBWhen I depress the button as instructed, it does not take. There is also a R/A (Resume/Accelerate) which one slides to the right that also does nothing. So, when this rain stops, I will check for fuse...
Re: Cruise Control Won't Reply #6 – April 11, 2018, 09:11:02 pm Had same problem on my Ford E450...Check this:https://www.youtube.com/watch?v=mICxnDTTIJI 1 Likes
Re: Cruise Control Won't Reply #7 – April 11, 2018, 09:16:45 pm This was the case with our '83 FL on the G-30 when we bought it. Found vacuum leaks, and when corrected, the cruise worked.Steve
Re: Cruise Control Won't Reply #8 – April 12, 2018, 04:27:11 pm Quote from: Lazy Bones - April 11, 2018, 09:11:02 pmHad same problem on my Ford E450...Check this:https://www.youtube.com/watch?v=mICxnDTTIJIMuch obliged.
Re: Cruise Control Won't Reply #10 – April 16, 2018, 07:00:47 pm Quote from: rodneyhelfrich - April 10, 2018, 11:46:31 pmStart with fuses. Is there engine vacuum at the cruise control vacuum servo( with throttle cable). Is the cruise control trying but not suceeding( working at 25-30 but not at 60)? The rubber parts on servo eventually fail. My 1986-7 K25 Suburban 350 carburated had the valve rubbers fail to seal. I replaced the entire vacuum servo. Valve rubbers were a GM part at one time. My K5 Blazer/Jimmy Diesel had human interface cable failure. The brains are behind the removable knee panel. I recall a common, on, resume/accelerate, set/coast 22 gauge wires inside a black cover. Unplug the cable from the brain box. Test all wires with a multi meter pressing the buttons for each function. An broken function loop requires the turn signal lever with the cruise control switches and cable be replaced. I found the lever as an after market part. If replacing, tie a sturdy waxed cord to the wire cable. Wrap some electrical tape around the knot area, to help the knot slide past all of the turn signal wires in the steering column. Pull the wires up the steering column leaving the waxed cord as a fish wire at the lever hole. The lever is held in with a spring detent. Pull it out. Tie the new lever wire cable to the string, wrap with electrical tape and pull the new cable back in. Snap new lever into turn switch socket. Plug the new wire cable into the brain box. Whew, lot of words for a simple task!The K5 diesel also had a vacuum pump failure. Serendipity decided to send a smile my way. Went in for smog-which essentially blew zeros. Vince the tech at A-1 hooked up my cruise control just because. Works like a charm! 1 Likes