Well it all started when the plastic vacuum line to the servo snapped right at the battery tray. Prior to this the cruise worked normal.

I replaced the plastic line after removing the battery/tray etc. I also noticed a small hole in the plastic line, but that section was replaced with the cracked section. Of course I cleaned up the tray, and the fender well section under the tray (rust from leaking acid).

Problem now is when pressing "set" on the cruise, I get a sudden acceleration like pedal mashed to the floor. If I leave it alone it keeps accelerating. I then start to press the set/coast button multiple times and the speed finally settles into desired speed. If I touch the brakes it turns off like normal, then when I hit resume, it starts to accelerate all over again, then I hit the set/coast button all over again.

Funny thing is, it all worked fine till I repaired the vacuum line.
Cable from servo looks good, no binding at the throttle linkage. Last night I "flushed" the set/coast switch with contact cleaner, and I unhooked the batteries overnight to see if it will force the computer to "relearn". Not sure if this will work. Have not tried cruise since this was done.

I have yet to test drive (will take a trip this weekend), but would like any advice. Next step is to clean TPS? New servo?
It seems like the servo or computer was "set" or "learned" to compensate for the small hole in the line. Now that there is no hole in the line is it "over compensating"?

I also wonder if the cruise/computer was "reflashed" while the hole in the line was in there. Heck, I even thought about putting a hole in the line to see if this corrects the problem.

Any ideas? Where is the best place to buy servo? (If I need one). Is it a reflash of the computer? TPS? Don't know what else to do at this point. Thanks, Kevin

 

Id clean the sending unit on the back side of your tranny first. Mine had gotten some oil on it and my speedo and my cruise werent working correctly . I cleaned it off and it worked like a champ. Always look for the cheapest/simplist fix first .
Scott

 

Kevin, take a look at this thread:

https://www.dieseltruckresource.com/...79702#msg79702

My reply then is still a WAG.

 

Hey guys, thanks for the fast replies so far. I will check the "sending unit" on the back side of the tranny. Could you be a little more specific? Is it a speed sensor? How many wires on it and it's location?

Yes, I would like to check the electrical connection at the servo as well for crud. Can't seem to get it to disconnect. Any tricks? I don't have the battery or tray removed right now, but it looks like I'm gonna have to pull it out again, can only get one hand down in there.

Still confuses me that it worked fine, then after replacing the tubing, the problem started.

Going to do a little hunting trip this weekend, so I will not be able to check things out till sunday. Thanks for the info and links so far, Kevin

 

Just a quick update: I don't know what I did, but cruise control is working normally. ;D

Not sure if it was disconnecting of the batteries, replacing a burned out 3rd brakelite bulb (both burned out), or electronic cleaner to the set switch, or just trying to get the connector at the servo apart (never did).

Anybody have any clue as to which of the above was the likely fix, then I sure would like to know. Thaks, Kevin