Cruise control working only sporadically

[veefer800canuck]

1994 Ranger SC, 4.0, 5 speed man, 260,000 KM

Factory cruise has lately not been working at all, until you drive the vehicle about 15 miles or so, then it starts working. Will work great for an hour or three, until you stop and shut off the truck, then quits working again until you drive 10-20 minutes, and magically cures itself again.

Haven't done any digging yet, was hoping there might be a common cause you could point me to and save some time.

Anyone???

 

[veefer800canuck]

Nobody????

 

[RonD]

More details.

Are the cruise lights on?
Can you set a speed but it just doesn't hold speed?

If set light goes on, does set light go off when you hit the brakes?

Is speedometer working?

Here is a diagram of cruise control:
http://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_Cruisecontrol_1of2.JPG

The vacuum dump valve on the brake can get flaky and leak.

 

[kimcrwbr1]

Pull all connectors apart and clean with electrical cleaner and use dielectric grease to put them back together. I had a similar problem turned out being a loose connector in the steering column for the clockspring. My guess is loose /bad connection or bad contacts in a switch. Intermittent problems are allways the worst to diagnose I like to do one thing at a time if you do a bunch of stuff at once you will never know where the problem was for future reference.

 

[veefer800canuck]

More details.

Are the cruise lights on?
Can you set a speed but it just doesn't hold speed?

If set light goes on, does set light go off when you hit the brakes?

Is speedometer working?

Here is a diagram of cruise control:
http://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_Cruisecontrol_1of2.JPG

The vacuum dump valve on the brake can get flaky and leak.

It's a 1994, no SET light.

The speedo is working fine. Cable driven.

In the first few miles of driving, you can hit ON, then SET, and nothing happens. Nothing at all. Truck just coasts. Press set 1000 more times, and after driving for about 15-20 mins, suddenly the 1002'nd time you press SET, suddenly the truck takes the SET and begins cruising at the selected speed.

Then, it works fine, you can RESUME after braking if needed, and so on. ACCEL also works, after it decides to play that is.

Stop for gas, shut off the truck, and the merry go round begins anew.

 

[veefer800canuck]

Pull all connectors apart and clean with electrical cleaner and use dielectric grease to put them back together. I had a similar problem turned out being a loose connector in the steering column for the clockspring. My guess is loose /bad connection or bad contacts in a switch. Intermittent problems are allways the worst to diagnose I like to do one thing at a time if you do a bunch of stuff at once you will never know where the problem was for future reference.

OK thanks, I'll start at the cruise actuator, and check all the connections there, and slowly work my way towards the steering wheel, if I don't find any joy.

 

[veefer800canuck]

And thank you RonD for the diagram, I'll print it and keep it handy when I get a chance to look at the truck.