Cruise Control Problems

Have a problem with my cruise control, Car is a 97 4.6HSE

Problem is the cruise control works below 5 degrees c untill engine warms up then you hear it click off. So what could cause this to happen as the full system works perfect untill the car warms up? ANyone had this problem on there car? Or any idea how i can get it to work all the time?

Thanks

Have you checked the little vacuum pipes that operate the cruise system in the engine bay?

-Wills

yup there all good, just don't understand how what seems to be a heat change can knock this system off???

As the temp rises in the egine bay the pipes will expand, you may have a small crack or pin hole in either one of the vacumn pipes or the bellows themselves. For the cost, change the vacumn pipes first, it's a cheap and easy way to either cure or rule out an issue. Not all holes/cracks are evident on a visual inspection

jdennington said:

As the temp rises in the egine bay the pipes will expand, you may have a small crack or pin hole in either one of the vacumn pipes or the bellows themselves. For the cost, change the vacumn pipes first, it's a cheap and easy way to either cure or rule out an issue. Not all holes/cracks are evident on a visual inspection

Click to expand...

I agree, and by the same token some of the mechanical adjustments such as the vacuum dump valve and its electrical connection and the stop lamp switch which is used in most Hella Cruise Control circuits can be on the edge of their adjustment and change with temperature.




1 Line Fuse 5 Amps 2 Speed Transducer 3 Brake Stop Light Switch
4 Brake Switch & Vent Valve 5 Clutch Switch & Vent Valve
6 Drivers Control Switch 7 Overspeed Relay 8 ECU
9 Vacuum Control Unit 10 Pneumatic Actuator 11 Fuse: Stop Lamp Circuit
12 Bulb Failure Monitor Unit 13 Stop Light Bulbs 14 To Speedometer
& Trip Computer

You system may be similar to the GR65 system above.

In addition, it would be worthwhile checking the ECU and Overspeed relay connectors and any local earths to their circuits. Something changing with temperature may be quite difficult to pin down, so cover the unexpected possibilities too.