i am not able to get my cruise control to work on my 86 bII 5spd/i have checked all the wire connections,vacuum lines,fuse..is there an easy way to check the system without the vehicle moving? what could the problem be? any thoughts is greatly appreciated!!

 

the speed sensor(s) in your tranny might be bad. the vacuum diaphragm under the hood might be toast. the switch on the vacuum diapragm might be toast. i don't think the cruise control is separate from the ECU? if it does have a separate "brain", that might be toast. the key is to eliminate the simple things first, which you have started doing

the control modules that i know about are -- ECU: kick panel on passenger (sometimes driver?) side up front. CC or ABS(?): on the driver's inner fender and one behind the kick panel behind the driver's side seat between front/rear seats. I haven't looked at the others besides the ECU to know which is which.

 

Pull the codes, if you're lucky-like I was- you'll get a vehicle speed sensor code & a simple 5 minute replacement of the VSS took care of it.

Does your horn work?

Have you got a wiring diagram & voltmeter so you can do some testing??

 

horn works fine.. i do not have a wiring diagram..where can i get one?

 

I like to troubleshoot electrical problems the EASY way, thats why I have the Ford "electrical & vacuum troubleshooting manuals" for my 87 Ranger & 95 Taurus.

Check it out at www.helminc.com

About 20 bucks.

 

I found an adequate wiring diagram for my '87 BII's cruise control at the local library in the automotive reference section. A lot of libraries will carry some professional manuals that will usually include good wiring diagrams of the necessary sub-systems like this.

 

Or, since you have internet access, you can go to http://www.autozone.com/repair_info.htm and select your vehicle, etc etc etc.

There are lots of resources -- I'm sure you could Google 'em as well. Never really thought about local libraries -- I guess because the one closest to me is about the size of a double wide trailer house... that, and I haven't been to a library and actually researched anything that way in YEARS

 

A few other items to check, I haven't yet seen mentioned:

1- There's a vacuum line that goes to the brake pedal under the dash, that kills any vacuum in the cruise servo unit, which expedites the cruise control system's disengagement when the brake pedal is applied. Make sure that hose hasn't developed cracks or separated from the mechanical valve that interacts with the brake pedal lever.

2A- If the transmission is manual, look for the switch on the clutch pedal lever. It's on the back side, making contact with the lever when the clutch pedal is released. Normally, the switch senses the slightest pressure on that pedal so as to electronically disengage the Cruise Control quickly. However, if that switch has loosened up from its fixture, it might be closed even when the clutch is NOT disengaged. Since it's ONLY used for the Cruise system, nothing else would be affected.

2B- If the transmission is automatic, usually a Neutral sense switch on it is used to deactivate the Cruise Control system. Not being familiar enough with the automatics, I can't say whether the switch closes or opens when the transmission is put in Neutral. If it opens, then check for loose wiring or connection(s) at that switch, or a bad switch. If it closes, and it's only one wire, then the signal for "Neutral" is 'Ground'. So, look for shorts to ground in that circuit. If it closes, and there are two wires, try disconnecting the switch. If the cruise control functions normally, replace the switch ASAP. Leaving it disconnected could result in engine damage from overrevving, not to mention possible safety hazards.

3- The main brake light switch is also used to electronically disengage the Cruise Control as soon as the brake lights are lit. If that switch has gotten loose, or perhaps the brake pedal is bouncing enough while driving (ever see a car ahead of you with the brake lights flickering?), it will prevent the Cruise control from staying on. BTW, if any fancy lighting or other gadgets have been added to the brake light circuitry, it could be adversely interacting with the Cruise Control's defeat logic.

4- If your Park Brake warning indicator bulb is burned out, it's possible the switch that lights that bulb is still closed constantly (or momentarily) without you being aware of it. Some Cruise Control systems check the status of the Park Brake, and if it's engaged, the Cruise will be shut down.

Hope this helps!

 

(1) I'm not particularly aware of a vacuum interlock on the brake pedal on an '86, but I'm not saying there isn't one there. I do know that (3) yes, when you hit the brake pedal, the cruise control 'shuts off'... or basically disengages throttle control. The only time it's 'off' is when the off button is depressed and you don't depress the on button afterwards...

(2A) uhhhh.... the clutch pedal SAFETY interlock switch might be piggy-backed and have two sets of contact for both the starting circuit and the cruise control.... but the main reason for a switch on the clutch pedal is so that you don't run your rig into something if you hit the starter with the tranny in gear... IF you forget to push in the clutch.

(2B) The neutral safety interlock may be like the clutch interlock -- piggybacked to disengage both start circuit and c/c as well....

(3) see comment (1)

(4) Yes, this is a valid option on some c/c's.

A Joe-neric troubleshooting chart:
http://www.autozone.com/servlet/UiBr...3d800f9511.jsp

 

thanks for all your help!! i will resume checking all these switches onece i get my slave cylinder replaced now i am unable to drive the darn thing!

 

I have a link on troubleshooting the 1989 CC in the tech info thread.