Cruise not working after removing upper Intake plenum to replace all the fuel lines.

[Angry Possum]

Hey all, I just replaced my fuel lines recently, I had to remove the upper intake plenum to get to the lines etc. The cruise worked prior and effortlessly. I checked all the vacuum lines, cruise control vacuum hub thingy etc but it's still not operating. What could I have unplugged and what should I look for, seems I obviously unplugged something. It's all connected correctly at the throttle body. Traced the vacuum line to the cruise hub. All good. Maybe something I may have unplugged under the truck.

1993 Ranger 4.0 XLT Automatic
Stock brake lights.

 

[BobSacamano]

You didn’t mention checking the fuse. Here’s the diagram in case you don’t have it.

 

[RobbieD]

Maybe something I may have unplugged under the truck.

Check and make sure that your brake lights are still working.

 

[BobSacamano]

Check and make sure that your brake lights are still working.

That would be a good check.

 

[Angry Possum]

Check and make sure that your brake lights are still working.

The taillights definitely work. That was the first thing I checked. I'll check the brake lights out later, thanks

 

[Angry Possum]

@RobbieD The Brake lights work. I guess I can check a fuse. Anything else to look for?

 

[85_Ranger4x4]

If you have a vacuum gauge make sure you are getting vacuum to the servo.

Check the hose that goes to the brake pedal dump valve and make sure it is connected.

Check vacuum line routing, I had an issue that drove me nuts where the hood hinge would pinch the feed line off as it ran over the top of the brake booster. Everything tested great in the driveway but it wouldn't work right on the road.

Make sure you didn't move the throttle cable going to the servo too much and damage it.

 

[Angry Possum]

If you have a vacuum gauge make sure you are getting vacuum to the servo.

Check the hose that goes to the brake pedal dump valve and make sure it is connected.

Check vacuum line routing, I had an issue that drove me nuts where the hood hinge would pinch the feed line off as it ran over the top of the brake booster. Everything tested great in the driveway but it wouldn't work right on the road.

Make sure you didn't move the throttle cable going to the servo too much and damage it.

Great info thanks. I was down in that lower area where the vacuum to the brake pedal is when I was attempting ro remove the original fuel lines in the engine bay area. It's very possible I could have pulled the vacuum line for the brake pedal. Also, I didn't check the fuse yet, but I will in a lil while.

 

[RobbieD]

@RobbieD The Brake lights work. I guess I can check a fuse. Anything else to look for?

@85_Ranger4x4 pretty much nailed it.

Look at this way- it worked, until you worked on the truck, and now it doesn't work. So most likely something unintended was done during the other work, and those "somethings" that unfortunately happen are fortunately usually simple to fix. You just gotta figure out what it is!

The factory procedure for a inoperative cruise has 8 relatively easy steps, and then four more that are more involved because they are testing the switches, servo, and speed sensor. The amplifier seems to be "test with a known good one", but the other stuff can be tested with a multimeter.

So first things, check that fuse, and check the dump valve. Then, these are the steps that a dealer would take to begin the troubleshooting, A1 through A12: