2008 Ranger cruise control problem

Discussion in '1998 - 2011 Ford Ranger' started by sunnyboy, Dec 15, 2012.

  1. sunnyboy

    sunnyboy New Member

    The cruise control on my 2008 Ranger FX4 is acting up. I can turn it on and engage the cruise (say for 90 kph) just fine. However, after about 5 minutes, it simply cuts out. That is, the dash cruise light stays on, but it simply ceases to hold speed.

    Once this happens, no amount of pressing on Res/set or coast does anything. If I turn it off then on again, it may or may not re-engage, but the cruise light on the dash comes on whenever you press set.

    What I have done so far:

    I ran the cruise control diagnostic procedure (hold off while turning on key, then press buttons in sequence). The static test passes, and I can hear the throttle cable working for the dynamic test (can't see it because I'm alone and in the cab). No blinking error lights at any point in the test.

    Also I checked the vehicle with an OBDII checker, and there are no codes active (green check).

    At first I thought it was a bad steering wheel cruise switch (maybe res/set) but the fact the cruise light comes on the instant you press set suggests something else is wrong.

    However, if it were one of the sensors (brake, etc) the diagnostic should have indicated that.

    Any suggestions as to what to try/inspect/test next?


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  3. Hooligan

    Hooligan Rangerholic!!

    I think you should have the cruise servo looked at. It is the black box behind the washer fluid with a cable running from your throttle body. Also check the connection to the throttle body
  4. OP

    sunnyboy New Member


    Well, the cruise problem is now fixed. It was the servo, as suggested by Hooligan.

    I had exhausted every other possibility, but new servos are $380 on Ebay and $450+ from dealers. Phoning around at wrecking yards, I found one out of the same year and model Ranger for $65. Picked it up and installed it in the parking lot as they are VERY easy to swap out. New (well, used) one worked perfectly.

    I took apart the broken one. They are a very simple device - there is a fairly complex circuit board behind protective gell on the side, a servo motor with 4 connections and a magnetic clutch with two connections. My guess is it's either the circuit board or the magnetic clutch OR the plastic gears meshed by the magnetic clutch that failed.

    What really annoys me about this whole process is that this servo is obviously (to me) something that could very easily be bench tested to see if it's A-OK or not. A simple plug harness (or even bare connections) could be applied and you'd quickly know if the board, servo, clutch or gears were bad (or it was all good). But in all my months of internet searching and dealer calling, there is nothing. The Haynes books are worse than useless regarding speed controllers, and the dealer always just said "bring the truck in". At $450+ for the new servo, that's not going to happen.

    So - anyone out there - have you heard of a bench test setup for speed control servos like this?
  5. Hooligan

    Hooligan Rangerholic!!

    Member Mfernandes of Uruguay is really good with stuff like that, he may be able to tell you if they can be bench tested or not

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