'94 Ranger XLT 4.0. A few months ago my cruise control quit working with the headlight on but was OK in the daytime. A couple of weeks ago it quit working entirely. I checked the fuses and all are good. I don't have the owners manual to show what fuses are where. Does anyone have a clue where to look for a problem? Thanks.

 

On the cruise control anomaly, have a look at the rear tail lights to see if one of the brake lamp filaments is burned out. If no brake lamps are working, check their ground connection back there.
If that checks out ok, have a look under hood at the brake switch & wire connection to it on the end of the brake master cylinder, maybe give the wire a wiggle & the switch a thump or two with a piece of wood or the like, to see if things wake up. If the switch wakes up, or its insulator is a Rust red color, consider changing it out for one with a Black color insulator material. I can't remember right now but If this year/model has the brake switch in cabin under the dash, connected to the brake pedal workings, have a look at its wire connection & electrically check its switch contact action to make sure its working.

On the no owner manual woe, maybe have a visit to one of your local salvage yards for a look into a glove box or two of a 94 Ranger for a manual. The Haynes repair manual covering that vintage had the fuse box layouts in them & many Library's still have the manual, so you could print a copy the fuse box page. Or you can sign up here BBB Industries- Premium Alternators, Starters, Power Steering Products and Turbochargers | TSB and Wiring Diagrams Database End-User License Agreement & look up Wiring & TSB info at no cost.

Some thoughts for consideration, let us know what you find.

 

Something to keep in your back pocket, and not that it's the cause of the problem but.....the VSS supplies data that is used by the engine, auto tranny, RABS, and cruise. It's been proven multiple times that this sensor can fail and affect one of those items and the rest work just fine, and unless it's affecting the ECM and as such, a code is thrown, or perhaps there are multiple items affected by the sensor failure, then this is one of the very few times that the only way to diagnose failure of a single system is to toss a new and known to be working correctly sensor into the vehicle.

 

Thanks gentlemen, I assume you are gentlemen, for the information. Last winter I installed led bulbs for the tail lights and that's, I think, when the cruise control stopped working with the lights on. I did the same thing on my '99 Explorer and everything is working fine there. I have a code on the truck now and have to read it. It's an OBD 1 so it's not so easy as the OBD 2 but I can handle it.

 

Reinstall the incandescent rear brake lamps & you'll likely cure your cruise control woes. The cruise control disconnect senses when the brake lights come on to disconnect/turn off, the set cruise control so we don't have an accident. If the rear brake lights don't draw enough current, as in broken wire, bad contact, burned out, or if using LED's, don't draw enough current, the circuit can act out.

 

If you don't have, can't borrow, or otherwise come by a OBD-1 code reader which makes extracting ECM codes easier & faster & more accurate, you can use one of these illustrations to construct a test circuit that'll blink, flash, or wave your OBD-1 codes. https://www.troublecodes.net/ford/

 

I changed the lamps back to incandescent and still no cruise control. I read the codes and they have nothing to do with the cruise control as far as I can see; 157 and 158, mass air flow problems. I have to get under the dash to check the brake light switch, it's not on the master cylinder. The brake light switch is in a place I can't get to but it does work to actuate the lights and feels OK.

 

-Ok that's good feedback, so lets think about this some more. Sounds like the brake light switch is working ok. Are Both rear brake lights coming on when you step on the brake pedal & going off when you take your foot off the brake pedal?
Will the cruise control still engage in daylight hours, as long as the lights are off? Will the cruise control operate if only the parking lights are on? Does the Dash cruise control on indicator still light up, or try to light up when you try to activate the cruise control?
Have you looked up the wiring diagrams, grounds & fuse for the Cruise control in the link I posted? it shows cruise in cabin panel fuse position 6 a 10 amp

 

Forgot to ask if the speed-o is ok, not acting out like not working, or jumping around/jittery, any ABS trouble light on, or auto tranny shifting problems, as if any are so that might suggest the rear ABS speed sensor belongs on the suspect list as those items also use its output to do their thing. Also the cruise control uses common ground position #202 so check the cruise control wire ground run & connection. You may have more than one problem now that the cruise seems to have stopped working at all.
More thoughts for consideration, let us know what you find.

 

Yes both brake lights come on and off. The cruise control doesn't work at all, lights on or off. I didn't notice if the light on the dash is on or off. I haven't checked the fuse but didn't see any ones blown when I looked yesterday. The speedometer hasn't worked in a year or so, it's stuck @ full speed but the cruise control worked after that. I'm going on a fishing trip tomorrow of a couple hundred miles total and will see if anything works which I doubt. Until Monday, thanks.

 

Thinking about this some more finds me wanting to ask, when the cruise control didn't want to work when the lights were on, was that After you had installed the LED tail lamps??

 

I'm pretty sure it was. It was last winter and I don't often drive at night or when the lights need to be on.

 

#1 there is no light on the dash #2 I used the cruise control all day yesterday and it worked #3 the tail light lamps were probably the problem #4 thanks for the help, I know more about the system now #5 case closed

 

Ok, no Dash cruise control light. Trying to remember back in the mid 90's when I began to test drive Ranger & B-Series Rangers if they had a dash cruise light. My 99 does but my 94 Taurus 3.8L doesn't, so maybe your 94 Ranger didn't have that feature, or maybe its burned out??? Maybe a member with a 94 & cruise, or with a 94 Owner Manual will chime in & enlighten us if that year had a dash cruise control lamp.

Anyway good to hear the cruise control now seems to be working ok & thanks for the feedback & closing out your trouble shoot.

 

the '94 ranger didn't have an Indicator Lamp.... also it don't matter if the Tail/stop light bulbe are even installed as the BOO just sends a 12V signal to the Cruise Module to Cancel so as long as the stop light switch works then "Cruise Cancel" will happen ....see the attached schematic and you will see that

EDIT: BTW if the dump valve is not adjusted correctly as in if it is leaking then Cruise will not engage ...