Troubleshooting Cruise

[troutwest66]

Trying to track down my cruise control problem. I used the diagnostic info that Peter Clark sent me and it told me the "deactivation" switch is bad and is located on top of the frame under the vacuum booster. Well, there is no part in that vacinity. Also, the switches in the horn pad are good, the tach works fine and the RABS light doesn't throw any codes (and the bulb is good). Is there anything in the rearend to look at, is there a deactivation switch on a '94 or do I have a bad servo and I need to head to the wrecking yard? I get power to the servo according to the diagnostic sheet.

 

[turbo69]

does the 94 have the vaccum deactivation over the brake pedal? That was the prob with mine. also, is the clutch pedal/starter interlock working right?

 

[troutwest66]

I don't think there's any vacuum involved with the newer cruise. I don't have that "coffee can" like the older ones. The clutch switch works fine and I don't think I have a problem with the break switch but I'm not sure on that one. If the break switch was bad are there any other symptoms? I'll probably go by Ford tomorrow and talk to the parts guy I know there. He printed some things off for me before. If I can just get a list of the components and how to test them....

 

[turbo69]

Mel-

Click Here

Download the file SPCDIAG.ppt. if you have power point. this may help, I don't know for sure. It may be the same stuff that Peter e-mailed you. I don't remember where I got that from.

As far as the break switch is concerned, if the brake lights work properly, then the switch is not to blame. If your brake lights stay on all of the time, then it is the culprit as the cruise computer uses the 12v signal to disengage the cruise.

 

[troutwest66]

Thanks, Bobby. I'll check that out and for the info on the break switch. I don't have PP but I'll see what I can view. The service guy at Ford copied some things out of the electrical and vacuum manual for me today so I'll get the meter out tomorrow. I've narrowed things down to: servo, clock winding switch in column, or speed sensor in the rearend. At least I think so. Oh, there is a ground under the right kick panel supposedly to check. Hopefully I'll get this figured out and fixed before the Montana trip on the 17th.

 

[troutwest66]

Cruise Control Update

Happened to be at my dad's working on my other rear parking brake cable (successfully ) and we were looking at the diagnostic stuff the service guy at Ford copied for me and on my truck there is a pressure switch on the front of the master cylinder that remains closed until the break pedal is depressed. Well, guess what?? Mine was stuck open and the cruise circuit can't be completed. $18 later at Ford and I got cruise again!!! I was glad to get it fixed too because we put 1406 trouble-free miles on The Hulk on our Montana vacation and I was in heaven with the cruise control!! So, the moral of this story is get the right diagnostics and check that pressure switch if you lose the cruise control.