Cuise control mystery

[Ryana]

Anyone know anything about cruise controls? I have a '93 ATX I have been working on(solving one issure at a time). I finally have it running great, and have fixed just about everything, but I can't figure out this cruise control. It has the cruise control servo box with the cable coming out of it and and the 10 pin(8 used) plug. I have wireing diagrams and have checked all the simply stuff. I have tried another servo box, I have followed the instructions on testing the switches from sho-times with the Light blue-black wired looking for voltage for the switch, every time I hit the on button with the harness unplugged looking for that 12v wake up voltage with my meter I see it but the horn goes off. I don't know what that is, maybe something to do with unplugging the harness I don't know. But I would say my switches work. My brake switch works its not causeing the problem. I do get a wierd resistance from my brake pressure switch, but I don't know what it is suppose to be. You would think open or close, but who knows. My speedo works, don't know if there is a seperate sensor for the cruise, my wireing diagrams are inconclusive on that point, they just say speed sensor, although there is mutliple plugs on the top of an ATX. Any suggestions. The speed is very difficult to keep steady on long trips that I take, and would love to have cruise.

sigh...
rz

 

[TYSHO]

I do get a wierd resistance from my brake pressure switch, but I don't know what it is suppose to be.

If this is the switch under the master cylinder, try replacing it, it can cause your CC not to operate. It's only a $20 part from Ford.

 

[NoSlo]

My cruise didn't work when I got the car, and it was the pressure switch and corroded/burnt connectors on the servo plug. I also had to find that the previous owner had cut the wire to the switch that comes from fuse 1 under the dash (the brake switch), probably because the fuse kept popping.

 

[rangerj]

The connection between the cruise switch and the cruise control runs through the clockspring. Have you tested the continuity between the switch and the cruise control servo?

The horn and the air bag are the other two items that are connected through the clockspring. the fact that the cruise control switch sets off the horn may indicate a short in the clockspring wires. If you go into the clockspring tests you MUST disable the air bag or risk setting it off.

There are numerous discussions on how to disable the air bag and test the clockspring circuits in the prior posts.

 

[Ryana]

I pulled the air bag out and the switches I have in both my '93s are the wire type that it looks like you have to pull the entire steering wheel off the get off. I went to the junk yard and pulled about 25 air bags out similar years and the switches all have a ribbon type connector that plugs into pin type male connector attached the the horn/clock spring assembly. I checked the pressure switch and all-data says the resistance is correct so I don't think it is that. It must be cruise set/coast/resume switch on the right side of the steering wheel. Without a replacement switch I cannot test it. Thanks for the replies. I am out of ideas.

 

[rangerj]

Yes, but have you checked for continuity between the switch at one end of the wire and the servo at the other end of the wire?