Cruise Control

[XLR8928]

My new motor doesn't care for my granny 73mph hi way speed... If I don't keep an eye on the speedo, I end up doing 85+mph! Has anyone had any luck fixing their cruise control? ..Where do I start?

[mixybro4]

My cruise control doesn't work or my speedometer. I like to keep it around 3500 RPMS, I figure everyone else is just driving slow.

[JhwShark]

I've never even tried mine...

[syoo8]

Your CC brain (located behind the clock, under the radio, in the center console) is dead. Very common. Don't get a used one, get a refurbished one. Some people have had success reflowing the solder in these brains. I've tried twice with no success.

[XLR8928]

Originally Posted by mixybro4

My cruise control doesn't work or my speedometer. I like to keep it around 3500 RPMS, I figure everyone else is just driving slow.

in my car that's about 88 mph!

[mixybro4]

Mines a three speed automatic and the speedometer only goes to 85 anyways so it wouldn't be much help! Im looking to fix my cruise control also. Hopefully someone knows where to start.

[mixybro4]

Originally Posted by syoo8

Your CC brain (located behind the clock, under the radio, in the center console) is dead. Very common. Don't get a used one, get a refurbished one. Some people have had success reflowing the solder in these brains. I've tried twice with no success.

I could've sworn someone told me the CC brain was in the front left fender. Behind the tire.

[syoo8]

Nope. That's the vacuum unit. Check the workshop manual, there's a detailed procedure for checking the CC brain in there.

[syoo8]

Section 27, pages 10-13 of the WSM, to be precise.

The Cruise Control (aka tempostat) amplifier is inside the center console, You remove the left carpeted cover (to the right of the passenger's right knee) and I think there are two or three bolts (and I think they were an odd size, like 7mm) which will release the amplifier.


The amplifier is a silver metal box, with some taupe colored plastic at the end, mounted on top of the tunnel next to the firewall. Remove the bolt on the right side.

The workshop manuals include a check of the servo by bridging terminals 3 and 5 on the plug. "Connect a push button switch on terminals 7 and 12. Turn on ignition and press the push button switch with engine stopped. The vacuum servo should move the throttle uniformly to full load position. This requires vacuum."

Remove the multiple pin plug. Then, with a voltmeter, you can check the pins. With ignition on:

Between terminal 5 and 12: battery voltage.
Between terminal 6 and 12: battery voltage when brake is pressed
Between terminal 8 and 12. battery voltage, unless you pull cancel on the CC lever, at which point it should go to zero.
Between terminal 9 and 12: 0 volts, unless you push the lever forward on the CC level, at which point it should show voltage.
Between terminal 10 and 12: 0 volts, unless you push the lever down (reset), at which it should show voltage.

With an ohmmeter:
Between terminal 12 and ground: 0 ohms
Between terminals 3 and 7: 14 ohms
Between terminals 11 and 12: should alternate between 0 and infinite ohms when you turn rear wheel.

If you check all these and they are "spec" then your CC amplifier is no good. Both of my 928s had this problem.

[Danglerb]

If the four pin speedo connection in the spare tire well isn't good, no speedo, no cruise.

[harborman]

There was a post here sometime ago for a place that rebuilds the cruise amp. I thought the cost was around $89.

[mixybro4]

Its really strange though, my speedometer works up until 25 and then shuts off.(drops back down to 0) Until I slow back down. I cleaned the 4 pin connector in the rear and it looks fine. I also checked the sensor on the differential. It also appeared fine. I think it is something inside the pod.

[syoo8]

Originally Posted by harborman

There was a post here sometime ago for a place that rebuilds the cruise amp. I thought the cost was around $89.

Yes, there were a few. Roger Tyson stopped using those services because the fixes didn't last... 928Intl is the only place now.