No Cruise Control - Help

[mjones]

Hello,

I have a 93 EB and the cruise doesn't work. I have checked the tail lights, the buttons on the steering wheel, and replaced the speed control amp. Still no luck. Any ideas?

Thanks,
Mark

 

[Jason94sport]

Might be the crusie servo. It's in the engine on the drivers side fender near the firewall. If your looking at the engine it's to the right of the master cylinder. It looks kinda cylinder shape. That was my problem. A new one from ford was $175 though!

 

[mjones]

Thanks for the info. As soon as I have the extra cash I will get one and see if that fixes the problem.

Mark

 

[MrShorty]

Before you dump more cash into it, have you verified that the cruise servo has vacuum? Have you checked the BOO switch and the brake dump valve? Is the cruise amp getting power? Checked the fuses? The last time my cruise didn't work, it was because the vacuum line to the servo had gotten pulled off.

 

[mjones]

O.K. Thanks for the advise. Well, I have found the cruise servo. There is one hose from the engine to the servo then a small hose that goes from the top of the servo to the bottom of the servo, then a hose that goes from the bottom of the servo to the firewall. Also a electrical conection on the servo. All hoses are in good shape. Does all of this sound right?

On the engine where the vacum for the servo conects, there are several hoses conecting there. One of which is cut and pluged. Will that make a difference?

I also checked the fuses and the are good.

How do I check and where are the BOO switch and the brake dump valve? Also how do I check if the cruise amp is getting power?

Thanks again for your help!
Mark

 

[MrShorty]

Sounds like the vacuum lines are routed correctly. Which one is cut and plugged? the one to the cruise control or another vacuum line?
BOO (Brake On/Off) switch is located on the pedal. If your brake lights work, then the BOO switch works, though this doesn't necessarily test the wiring between the BOO switch and the cruise control.
Dump valve will be at the end of the vacuum line that goes from the CC servo to the firewall. The dump valve should hold vacuum until the brake pedal is pressed.
To check for power to the cruise, you'll need a wiring diagram (Probably need a Ford or equivalent manual. Most DIY manuals don't have cruise control wiring diagrams). Identify the power wire to the cruise control, and measure the voltage between that power wire and ground.

 

[newbi]

Something real simple to check is at the throttle body...make sure the linkage is hooked up and not broken. It'll have slack at an idle. Also, the buttons on the steering wheel get crudded up so make a serious effort when setting them for as test of the cruise. Chances are it's the BOO switch...let us know what you find, OK?
PS- also , if the above doesn't solve the problem, crawl under the truck and on the drivers side of the tranny there will be a VSS(varible speed sensor). It'll have wires going to it that may of come loose or broke. The VSS sends info to the cruise and ECM.

 

[KPT]

PS- also , if the above doesn't solve the problem, crawl under the truck and on the drivers side of the tranny there will be a VSS(varible speed sensor). It'll have wires going to it that may of come loose or broke. The VSS sends info to the cruise and ECM.

Wouldn't the speedometer not work is the VSS wasn't working though? Or are first gen's mechanical speedometers?

 

[MrShorty]

1st gens do use a mechanical speedometer cable to operate the dash speedometer.