Troubleshooting Bendix Fast Idle/Cruise Control on 89 35FC 3208 ATAAC

[Ralph L. Fullenwider]

PT cruise/air throttle/high idle

Some time back, I posted to the files section, a couple of files on how
these systems work and inter act.

As for the FC's it is a little difference because the factory <BB> dip
switch settings allowed the fc cruise controls to work slightly different
than the PT's.

As for the problem in the FC, where it is on or off and no in between, I
would suspect the CC5 potentiometer internal of the cylinder to be faulty.
All this can be checked with a decent Multimeter and following the checks
in the Bendix manual that should be in the blue box.

The only thing I have found that was done a little funky form the factory,
is how the clutch switch was wired up since there are no clutches in the
Birds and that was done with 2 solenoids in the system. I have actually
taken those out of the system to get my cruise working properly and that
was done with a pair of side cutters! One snip and you have cruise.
Now the problem with the break pedal not canceling the cruise is or has
generally been a bad set switch or corroded contacts in a connector. And
can usually be cleared up by cleaning the pin contacts coming from the
Bendix control.

Remember that our Coaches put out 120 to 130 psi of air and there is a
regulator with the bendix set up to drop that pressure to 80 to 90 psi,
thereby making the working difference of only a few psi differential that
the electronics of the bendix system reads and enacts on.

>

Safe travels,

Ralph and Charolette Fullenwider
84FC35
Duncan, Oklahoma