GoreMaker
Newbie
The cruise control on my 1999 Suburban K1500 gasser has been wonky and unreliable since I bought the vehicle a little over a year ago.
Most of the time, it works fine. But sometimes, when going uphill, it allows the speed to drop way too much (like 10+mph) before the transmission finally kicks down a gear. I can resolve this by gently tapping (not pressing) the go-pedal with my foot, at which point the transmission will finally downshift and the speed will go back to where it's supposed to be, except then it'll be 1-2 mph higher than it was before the uphill and take a few miles to return to normal.
After using cruise control for a while (30+ minutes straight), sometimes it just cuts out and stops working with no error code in the PCM. When this happens, I can re-engage cruise control for a couple seconds before it cuts out again. It doesn't work right until I stop driving for an hour or so, then it's good to go for another extended period of time.
These symptoms lead me to suspect that the servo motor inside the cruise control unit might be on the way out. These are older cruise control units with an electric motor that actuates a second throttle cable. If that servo is failing, it would struggle to move to the correct position when the engine load increases, and it could be overheating after extended use.
Is this a common issue? Is there a way to fix the cruise control unit without replacing it? Maybe some soldering repairs on the control board to ensure the servo is receiving all the current it needs? Or should I just bite the bullet and buy a new unit? I've got a long road trip coming up next week, and I'd really like cruise control to function reliability.
Most of the time, it works fine. But sometimes, when going uphill, it allows the speed to drop way too much (like 10+mph) before the transmission finally kicks down a gear. I can resolve this by gently tapping (not pressing) the go-pedal with my foot, at which point the transmission will finally downshift and the speed will go back to where it's supposed to be, except then it'll be 1-2 mph higher than it was before the uphill and take a few miles to return to normal.
After using cruise control for a while (30+ minutes straight), sometimes it just cuts out and stops working with no error code in the PCM. When this happens, I can re-engage cruise control for a couple seconds before it cuts out again. It doesn't work right until I stop driving for an hour or so, then it's good to go for another extended period of time.
These symptoms lead me to suspect that the servo motor inside the cruise control unit might be on the way out. These are older cruise control units with an electric motor that actuates a second throttle cable. If that servo is failing, it would struggle to move to the correct position when the engine load increases, and it could be overheating after extended use.
Is this a common issue? Is there a way to fix the cruise control unit without replacing it? Maybe some soldering repairs on the control board to ensure the servo is receiving all the current it needs? Or should I just bite the bullet and buy a new unit? I've got a long road trip coming up next week, and I'd really like cruise control to function reliability.
