Cruise Control and Cold Weather

[KYProtege5]

Has anobody else experienced problems with their cruise control during cold weather? My cruise works absolutely fine during the spring, summer and fall... but when the temps drop to the mid-40s and below, my cruise doesn't want to engage. The cruise light on the dash will light up, but it just won't engage. I have to hold the cruise button down and hold the gas steady for a short time for it to engage... if it will at all. Once the temps get up into the 50s and above, I have absolutely no problem at all. Anybody else experiencing this?

BTW - absolutely love this forum as a resource. I don't really mod my P5, but I try to care for it as best I can... and this forum is a great resource for day-dreaming as well as practical information!

 

[CheeseHelmet]

Does it start working better when the engine warms up? If so, check the vacuum line from the intake manifold to the cruise control actuator, it might have a small hole in it.

 

[KYProtege5]

The temp of the engine doesn't seem to affect it one way or the other. I could have been driving for a solid hour + and the cruise still won't engage in sub 40 temps. Or at least it won't engage consistently and without tinkering. It all seems to be about the ambient air temperature. Warm weather = no problems. Cold weather = fussy cruise engagement.

 

[CheeseHelmet]

I think the problem is with the actuator, you say that the green "cruise" light comes on but the car doesn't actually maintain speed, right?

This means that the cruise control module is receiving commands from the switches on the steering column but isn't able to maintain speed. If there was a problem with anything else (clutch switch, brake switch, tail lights, etc) the "cruise" light wouldn't even come on. This means that the module can't control the actuator, either because of faulty wiring or the actuator is somehow broken. If you're completely certain that it only fails during cold weather I'd lean towards the actuator being the problem, if it were the wiring it would probably act up more randomly or when there was more humidity.

One simple thing you might want to try is cleaning the actuator's connector: just disconnect it, spray it with some contact cleaner (or wd40 if you don't want to buy contact cleaner) and then plug/unplug it a few times. I doubt that'll fix the problem but at least we can rule out a corroded connector.

From there I'd recommend looking at page 01-20-4 of the service manual, it shows you how you can test the actuator with an ohm meter and it also has a test where you connect the actuator to the battery with the engine running to see if it can move the throttle. If you were able to replicate your problem using this method on a cold day then you'll know for sure that the actuator is bad.

 

[spud_joat]

KYProtege5,

I am curious if you ever found a solution to your cruise control not working in cold temps. I have a 2003 Protege LX that I have been struggling with the same symptoms that you've described and have never found the problem. In colder outside temps I press the set button and the cruise light on the dash lights up but it will not actually set the cruise. In warmer outside temps the cruise sets just fine. I have replaced the vacuum line between the manifold and the actuator. I can hear the control module relay under the passenger dash click when engaging & disengaging the power to the cruise control at the steering wheel. I have run the diagnostic tests by using the flashing cruise light on the dash and everything seems to be responding correctly. "Resume/Accel" button flashes a code 22, "Set" button flashes a code 21, pressing the Brake flashes a code 31, driving over 25mph flashes a code 37, sitting in Park or Neutral flashes a code 35. All the inputs to the control module seem corrrect. Last night I cleaned the actuators electrical contacts with contact cleaner, per the advice of CheeseHelmet, but it is too early to tell if that had any impact. I also checked the resistances R1, R2 & R3 at the actuator terminals per the service manual 01-20-4 and they all check out correct. Temps here are still above 40 degrees but it will be getting cold soon. Any advice would be appreciated. Thanks.