89 Continental Cruise Control Inop!

[My89Conti]

Hi fellow Lincoln lovers.....I have an '89 Continental and the cruise control is inoperative. I have changed out the transducer, but to no avail. I checked all switches for proper operation with a multimeter and all appears normal. All switches are normally open. Any ideas folks? According to the wiring diagram the cruise control actually functions via the EEC computer. I am hoping this is NOT the problem!!!!!! Peace.

 

[MichiganTeddyBear]

ok.. speedo works right I assume....and all fuses are good. no vacuum leaks?? I think its a vacuum operated servo, but not positive.

does 89 have the cruise switches on the wheel, or on the turn signal?? if on the wheel, I would suspect the 'clock spring' inside the wheel/column.

if its on the turn signal.. possibly multifunction switch.

it is VERY unusual for one function of the EEC to fail an rest work ok. I am willing to bet a problem elsewhere (wiring, other part failed, ect).

With the number of these cars avail in the junkyards, you might score an EEC there if needed. I have a 90 parts car, I can probably get some parts off it if needed. To best of my knowledge, the cruise on it was working when it got parked.

I will consult my manual (altho its for a 92) and see what I can find as possible causes for the problem when I get home tonite.

 

[1989 Signature Series]

cruise switches on my '89 are on the wheel
my '90 marquis sometimes would malfunction bacuse the arm/rod on the servo was bent a little. it had the turn signal mounted controls and it took a while to figure THAT one out it was not an obviously noticable problem.

when vacume was applied the arm/rod would rotate sometimes and the little bend would stop it from moving far enough to set.

Welcome to the Forum

 

[MichiganTeddyBear]

a clock spring being bad can also cause horn problems... altho you can still have horn without cruise on a steering wheel mounted setup if you have a bad clockspring.

if the horn don't work (and all else checks ok in that circuit) then the clockspring is probably bad

 

[MichiganTeddyBear]

ok.,.. some info, from the 92 service manual.... your milage may vary for the 89.

the cruise on the 92 does NOT go thru the EEC... but thru a seperate speed control amplifier, which is located behind RH side of I/P, near top of cowl panel. looks like its fun to get to.

1st. make sure you have good fuses.. yes, plural..fuse 1 and 5 (both 15A). fuse 1 is probably good, goes to other stuff I assume is working (turn/stop/hazard lamps), fuse 5 is only for speed control.

if the stop lamp switch (mounted near top of brake pedal assy, with LG/R and LG wires) is stuck closed, the speed control will think brake is on all times. Also check the vacuum dump valve and the line(s) going to it (may only be 1, with other end open to air).. it dumps the vacuum from the servo when brakes are applied. the manual don't show it well, but it is probably also mounted near top of brake assy.

Also the modulator valve (part of the servo assy) could cause it... there are 2 solenoid type coils connected in a way that they can regulate the amount of vacuum applied to the servo itself.

there is also a specific method of testing the switches and clockspring assy...

here it is...
Disconnect the speed control amplifier connector, and measure the resistance between the LB/BK and O wires while pressing the following buttons on the speed control:

OFF button= 0-4 ohms
Coast button= 114-126 ohms
Set/Accel button= 646-714 ohms
REsume button= 2090-2310 ohms.

hope this info helps.. remember its from the 92 EVTM manual, and may be different than your 89. I have found it very close to my 91 conti as well as close to my 90 parts conti.