Avoiding my cruise control

[colinlikens]

OK, call me crazy...  I have never used the cruise control in my '73 Eldorado.  As a kid I remember that once my grandfather's Grand Marquis got old if anyone ever used the cruise control it would cause other electrical malfunctions in the car.  As a result, since I started driving the car in April I haven't wanted to use the cruise control enough to risk discovering if there are any gremlins that would be triggered by it.

Since I am consistently impressed with how much fellow members of this forum know, please tell me: is there any reason to avoid trying the cruise control?  Please understand that I'm not worried the car will be uncontrollable.  Rather, I don't want to interrupt my summer driving fun with an unexpected electrical malfunction in essential systems.  Everything else in the car works great except for the A/C and power locks.

Thanks.

Colin

[Dan LeBlanc]

Give it a shot.  There's only one way to find out if it works.  YOLO!

[mgbeda]

Those cruise controls aren't really connected electrically to anything except their own switch.  The connection to the throttle is through vacuum servos and to the speedometer is through the speedometer cable which is always turning whether the cruise is on or off.  I'm pretty sure the cruise even has its own fuse, so the worst thing that can happen electrically is the cruise control damages itself.

I think the Ford systems had more electronics to them.  I remember they had a bunch of buttons on the steering wheel which was very high tech in the 70's.

-mB

[waterzap]

Try to use it. My bet is that it doesnt even work, or not well.

[TJ Hopland]

I agree with the others in that it does not really tie in with any other systems so give it a shot.   

Its a very basic system.   The 'brains' if you can call something that simple having brains are in the inline gearbox thing the speedometer cables run through.   There is really nothing electronic in it.   Its got a couple solenoid like coils and contacts in it and I don't think they were common to fail.   The rest is mechanical which can get worn or gunked up.  Its kinda like a speedometer mechanism inside.   When you engage it the basically a sliding valve clamps onto what would be the needle end of the speedometer mechanism so when the 'needle' goes up the valve slides one way it vents the the servo so the throttle releases a bit.  When the 'needle' drops it opens a valve to vacuum which pulls in the servo and throttle. 

[76eldo]

Colin,

Using the cruise control in your car will not make any other electrical items unstable.  It will either work, or wont work, on it's own.  In addition to the electrical part, there are vacuum controlled parts as well.  IF if does engage, make sure that a gentle tap on the brake pedal immediately disengages the cruise control.  If it doesn't, turn off the switch and don't use it at all until you get it looked at.

Good luck!

Brian