Cruise control not working on 1994

[1994xlt]

I have 94 Ranger with cruise control and I cannot get it to work, I’ve tried a couple dozen times, I think one time it MAY of tried to work because my speedometer kinda froze at a speed and then dropped down 5mph but I don’t know, I took the steering wheel cover off and looked at the switches nothing looked obviously broken or corroded so I assume it’s probably another issue? What could it be and were should i start

 

[RobbieD]

Check that you have a speed pulse generator on the speedo cable where it plugs into the transmission, make sure that it's plugged in and the wires aren't damaged.

Check that the servo throttle cable is connected at the throttle, and it's not frayed or excessively stretched. Make sure that the servo has vacuum on the flexible hose when the engine is running.

LED taillights, or stock incandescent bulbs? LEDs will block the cruise seeing ground when the brake lights are off. Power (brake pressed) turns the cruise off, but it must also see ground on that circuit before it will operate.

When you're testing it, push "ON" first, then at a steady speed (a "highway" speed is best) with your foot on the gas pedal press "SET". Backing your foot off, you should fell the throttle surge if it's working.

 

[1994xlt]

Check that you have a speed pulse generator on the speedo cable where it plugs into the transmission, make sure that it's plugged in and the wires aren't damaged.

Check that the servo throttle cable is connected at the throttle, and it's not frayed or excessively stretched. Make sure that the servo has vacuum on the flexible hose when the engine is running.

LED taillights, or stock incandescent bulbs? LEDs will block the cruise seeing ground when the brake lights are off. Power (brake pressed) turns the cruise off, but it must also see ground on that circuit before it will operate.

When you're testing it, push "ON" first, then at a steady speed (a "highway" speed is best) with your foot on the gas pedal press "SET". Backing your foot off, you should fell the throttle surge if it's working.

I have stock taillights.i will look up what a speed pulse is and were if is and the servo too I probly know what they are just dunno what they look like.

 

[1994xlt]

I have stock taillights.i will look up what a speed pulse is and were if is and the servo too I probly know what they are just dunno what they look like.

Guys I couldn’t find much about this I might be looking for the wrong thing could somebody pics picture on here?

 

[rumblecloud]

There is also a printed circuit board (aka amplifier) mounted under the dash just above the glove compartment that could be acting up. You have to drop the glove box compartment down by pressing inward on the sides.
I'll add an image in a sec...

 

[Curious Hound]

Guys I couldn’t find much about this I might be looking for the wrong thing could somebody pics picture on here?

In your case, with 4x4, your speedometer cable is connected to the transfer case, driver side, near the back end. In addition to the mechanical cable for the speedometer, it should have a device there with wires to give an electrucal speed signal for the cruise control.

 

[rumblecloud]

here are a few images of it after removal. I think you'll need a 5 mm socket.

 

[fastpakr]

If you can lay your hands on a Mitchell Manual for 1994, there will be a clear sequence of steps in there for diagnosing the fault. I used that on my old 94 Explorer to narrow it down to the cruise amplifier under the dash.

There’s a small chance I still have mine. Somewhere. If so, I’ll post the info here. Otherwise, poke around online and see if you can find a copy of it. Worth it’s weight in gold.

 

[Curious Hound]

In the mean time, here are the pages from the EVTM. This is 93. But 94 should be the same.

 

[85_Ranger4x4]

If you can lay your hands on a Mitchell Manual for 1994, there will be a clear sequence of steps in there for diagnosing the fault. I used that on my old 94 Explorer to narrow it down to the cruise amplifier under the dash.

There’s a small chance I still have mine. Somewhere. If so, I’ll post the info here. Otherwise, poke around online and see if you can find a copy of it. Worth it’s weight in gold.

Factory shop manual and EVTM were a lifesaver for when I added cruise to my truck.

Mine is a older system and is different than a '94 though.

No competition for the idiot that routed the vacuum line to the servo in a place the hood hinge would pinch it when the hood was shut. It passed every check with flying colors until the hinge started leaving a mark on the hose and I put two and 2 together lol.

 

[fastpakr]

https://ebay.io/m/kNCIrA

 

[lowspeedpursuit]

RobbieD covered all the first steps immediately; the only thing I would add is to remember when testing that system it has a minimum speed of something like 35mph.

If you try to test it at 30mph and down, it will never set.

 

[RobbieD]

And another common thing to check, that I forgot, is to make sure that the dump valve is seated on the brake pedal. It just pushes into a mounting clip, and it can back out which reduces or eliminates the vacuum that's supplied to the servo.