I was wondering if the cruise control on my 85 F150 Xl lariat is vacuum powered or electrical? I currently does not work... Any ideas?

 

Does your horn button on the pad work?

 

A little bit of evrything, electical & vac.


hardy

 

s is mainly vacuum. Without it, it will not operate. You should see the mechanism on the drivers side near the firewall. Check the lines there first. Then, there should be a vacuum dump attached to the break pedal. Check that this line is not leaking at all. If both are good, then it is time to check for power. Under the dash to the right of your leg, you will see the computer for it. Two screws hold it in place. Check connections and clean them. After that, I am at a loss. Possible problem with on/off button in steering wheel, etc.

 

A common failure is the chain connecting the servo (actuator) cable to the carb linkage. It's that light-duty beaded chain stuff like you see on a ceiling fan or antique light fixture. If that breaks, the speed control won't work.

 

The EVTM has a good troubleshooting guide. This is for an '86, but your '85 should be very similar:

Speed Control - ???Gary's Garagemahal