Brad, the next thing I'd check is to unplug the harness and check for a ground via the pin connected to the R/LB wire.... if you had a bad ground there, all the inputs could be working fine, but with noplace to go, the circuit would still be open.

My only other guess would be a bad input from the rear wheel speed sensor.... That would typically be tied into the ABS, but it's possible that the lead from the sensor to the servo only might be bad..... not sure how you'd check that though.

-Joe

 

I'm new here and have the same problem with my 88 F-150. I had the steering wheel off for ignition switch work. Shortly there after, the cruise quit working. I pulled the horn pad off and checked voltages at the connector. With the key off I get 12.57 volts on one contact and 0 on the other. With the key on, I get 12.57 on the one contact and 7.58 on the other. Would this be normal. Also when I had the wheel off, I noticed the outer brush is flat across and the inner brush is stepped. Is this also normal? Is the speed control amplifer under the dash made of plastic? I see one under the radio with 2 plugs, but don't see a W/PK wire going to it.

Thanks
Mike

 

94 f150 with cruise not working . I did the ohm checks on pins 5 & 6 , voltage on 9 & 7 , even checked pin 4 to make sure it had no voltage till brake was pressed and still no cruise . Didn't check pin 10 for ground . All brake lights work . Oh and I had 12 volts on pin 5 when the on button was pressed . I guess this leads me in the direction of a new servo . Where is a good place to get one other than the dealer . Any help would be appreciated . Thanks

 

Have you done the on board self-test?

Self-Test Diagnostics

WARNING:
This test is a key on engine off (KOEO) test only that is conducted in park only with emergency brake fully engaged.

1. Enter self-test diagnostics by depressing the speed control OFF switch while turning the ignition key ON, making sure the engine does not start and is not running. The speed control indicator on the instrument panel will flash once to indicate that speed control module entered the diagnostic mode. Five additional flashes at this point indicate a defective speed control servo. Release the OFF switch.

2. Press the remaining switches in this sequence: ON, RESUME, COAST and SET/ACCEL.

If the ON switch is not depressed within five seconds after entering the diagnostics mode, the module times out and the procedure must be started over.

The speed control indicator lamp will flash as each switch is depressed. Press each switch in the sequence immediately after the indicator light goes out for the previous switch.

Note:
There will be a slight delay when the last button is pressed and the lamp flashes.

3. A lamp flash with the last button (SET/ACCEL) indicates that the static test passed. If the lamp does not flash with the last button and there are no additional flashes of the lamp, the switch is defective.

If the lamp does not flash with the last button, and additional flashes occur, follow the chart below for trouble codes:

— 2 flashes - BPP defective, circuit is defective, brake applied, CPP switch or jumper (if equipped).

— 3 flashes - deactivator switch is open or circuit defective.

— 4 flashes - vehicle speed signal is out of range or circuit is defective

4. Immediately (.25 second delay) after the static test, the speed control servo does a dynamic test by automatically actuating the throttle lever from 8 mm (0.315 in) to 12 mm (0.472 in) of travel from the idle position. During the dynamic throttle pull, observe throttle movement to witness any binding or sticking of the speed control cable and correct connection of speed control cable to throttle lever. Make sure the throttle returns to the idle position.

5. Return the ignition switch to the OFF position and proceed to the Symptom Chart.

 

I tried to enter the diagnostic mode but can't even get the speed control light to come on . Actually I've never seen the light on . Does this test work on a 94 ?

 

I also tried to do the test on a 94 f 150 and no speed control light came on. Any other suggestions? Also if the servo is bad where do you suggest to get a new one? Ford wants $ 517.49 plus freight and so far I've not found and aftermarket source.

 

I don't think that the test will work on our model year . I don't see a speed control light anywhere in the cluster . All my voltage and ohms check seem to be ok . Must be the servo but there's no way I'd pay that much . I am going to a few pick-a-part places around town and will post the results . No guarantee that a used one will be good but it's going to be quite a bit cheaper .

 

Do we know what years the diagnostics above apply to

 

I dont think any models before 98 -99 had a speed indicator light on the dash I know my 96 doesnt