95 bronco cruise control not working

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Cruise control not working

• Thread starter colinrich76
• Start date Jul 2, 2014

colinrich76

I have an 88 B2 and I cannot get the cruise working. I ran by a local junkyard and was able to pull a donor servo and a few speed amplifier modules. None of these did anything to get it working. I've checked for vacuum leaks and also checked the switch at the top of the brake pedal, all of these are good. Fuse is also good. I also pulled off the steering wheel cover and checked all of the contacts for the buttons, all looked good and had good contact. Throttle for the cruise servo is also adjusted appropriately. All of this to say, I'm totally stumped. I've got to be overlooking something here. I've scoured the forums and haven't found anything that I haven't tried (listed above). Anybody got any ideas?  

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Any mods done to the truck? I think I read a post somewhere that LED tail/brake lights mess with the CC.  

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The electronic cruise control system consists of the following components: Control switches Servo/control unit (throttle actuator) Speed sensor Stoplamp and deactivator switches The throttle actuator/control unit is mounted in the engine compartment and is connected to the throttle linkage with an actuator cable. The control unit regulates the throttle actuator to keep the requested speed. When the brake pedal is depressed, an electrical signal from the stoplamp and deactivator switches return the system to stand-by mode. This system operates independently of engine vacuum, therefore no vacuum lines are required. Fig. 2: Electronic cruise control system components  

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The vacuum controlled cruise control system consists of the following components: Control switches Servo (throttle actuator) Speed sensor Clutch switch (manual transmissions) Stoplamp switch Vacuum dump valve Amplifier assembly The throttle actuator is mounted in the engine compartment and is connected to the throttle linkage with an actuator cable. The speed control amplifier regulates the throttle actuator to keep the requested speed. When the brake pedal is depressed, an electrical signal from the stoplamp switch returns the system to stand-by mode. The vacuum dump valve also mechanically releases the vacuum in the throttle actuator, thus releasing the throttle independently of the amplifier control. This feature is used as a safety backup.  

Hope something there helps. Vacuum circuits can be a pain, so you really have to check those closely. Let us know what you figure out.  

Thanks guys! No mods done, it's all stock electrically. Thank you for the diagrams! The stoplight switch looks brand new(just bought the b2 a month ago), but it's worth replacing just to check. The vacuum lines are solid, which is where I figured initially the issue would lie. Throttle actuator is solid, it just doesn't seem to turn on. I'll keep tinkering and keep you guys posted!  

Alright guys, quick update: I crawled under the B2 to check the speed sensor and there is no wiring harness plugged in! So, that would do it, I just can't seem to find what should plug into it, there are no open plugs in sight. So I'm assuming the speedometer cable was changed, but changed to one that doesn't have the cruise option? I'm not totally sure what else could have happened here.  

Well, that may have been a problem, but not THE problem. Went ahead and replaced the VSS and the connector for the cruise. Nothin. Man, I was almost certain that would get it.  

do the hazards work?  

Thanks for the diagram! Yes, the hazards are working.  

Not sure if this matters, but the wires to my vss are different colors than the diagram specifies. Both are light blue, one with a strip of black.  

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Cruise control not working in a 93

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I have a 1993 bronco with a 5.0 and m5od(manual) transmission. My cruise control hasn't worked since I got the truck and was wondering what to check that might fix the problem. I have no lights on the dash, when the buttons are pressed no lights light up, and the horn still works. any thoughts or test I could run? Clock Spring? Vacuum Lines?  

I don't know much about the 93 but i had a cruise problem on another 90's ford that ended up being the brake light switch. Not sure if ford was still using a vacuum dump in 93 or if it had moved to full electrical...  

• If the amber RABS indicator in the instrument cluster stays lit when the ignition switch is in the RUN position, then refer to servicing the rear anti-lock brake system before continuing with the speed control diagnostics.
• Does the horn work? If not, check the horn circuit fuse, horn relay and horn circuit wiring.
• Do the stoplamps light when the brake pedal is depressed? If not, check the stoplamp circuit fuse, stoplamps, wiring and stoplamp switch.
• Look for loose or unseated speed control servo connector pins.
• Check for broken wires at the connectors.
• Check for speed control servo cable adjustment.
• Check for broken or bound speed control servo cable.

There are no dash indicator lights for the speed control system. 1993 was the first year the F-Series/Bronco used electronic controlled speed control that uses the fire prone Brake Pressure Switch. The BPS is located on the rear brake line near the RABS hydraulic module. Literally under the driver's left foot. As stated the BPS is FIRE PRONE that has caused fires in 100s of Ford vehicles. The first thing to check is to see if the recall harness w/fuse is installed. 1993 is a one year only where the BPS is along the driver side frame rail/rear brake line. 1994 and later trucks the BPS is on the brake master cylinder. If the recall harness is not installed then remove the connector to the Brake Pressure Switch NOW. Then call the nearest Ford dealer to get the recall harness installed. If the recall harness/fuse is installed, verify the fuse is good as well as the fuses in the fuse panel. If so, then check the signal inputs into the speed control servo. Good inputs and power point to a bad servo, which is common.  

Can you show us a pic of what that looks like? I've checked the ford recall site and see no outstanding recalls for my '95, but I would like to verify visually.  

My 97 F250 OBS just had this problem. It has the red switch and recall fuse harness that is mounted to the master cylinder and it failed, keeping the CC from engaging. I just happened to have an old red switch kicking around that was swapped with the improved switch in another vehicle. For starters I would probe both sides of the red switch. There should be power on both sides, even with truck off. If you have power only on one side, you may have found the problem. If you still have the red switch I would recommend you buy and install the new style. Very easy to do and only about $30 as I recall for the Motorcraft replacement. The new switch will do away with the added on fuse harnesses and it comes with a short harness to adapt to a different harness connector style.  

There have been other posts on here with cruise control problems, that were traced back to using LED brake light bulbs. The resistance in the stock filament brake light bulbs is required by the cruise control module.  

Thanks for the information I'm gonna look into some of the suggestions(the ones that match up with the parts on mine).  

Does the vacuum canister that looks like a coffee can have anything to do with the cruise control?  

No it does not. The 1993 and later Speed Control system is electronic controlled. The 1992 and earlier trucks used a vacuum servo that had a vacuum reservoir behind the driver side headlight on most models. The coffee can shaped reservoir on the passenger side inner fender is for the emissions system (EGR/TAB/TAD).  

Since it was an easy replacement I bought and replaced what Native_Viking posted and that fixed my cruise on my 96.  

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