[william]

My cruise worked fine on my 75 RC until I swapped the tranny to a 4 speed, and now the cruise doesn't work. I followed the tests in the FSM, but I am no closer to a solution. The relays are clicking inside the servo when I actuate the switches, but it just won't kick in while I am driving. Is there anything else I can check on this, short of replacing the whole unit? I can't see why it would just stop working. Could it possibly have anything to do with swapping from auto to manual? Stumped on this one...
william

 

[Chump]

You have a coil in the servo thats called the hold coil and also a low speed switch that makes and breaks according to speed. The switch makes and breaks at at about 30-35 MPH and it supplies a ground to the hold coil. There is one more step in the FSM that needs to be followed and thats the one where it says to engage the speed control with the wheels off the ground at 35 MPH..this is dangerous for the average person...you could do the same test by going down the road at 35 and using a long lead on the test light to see if the circuit works. does the speedometer work correctly? Is the stoplight switch wired up correctly?