Vacuum lines, clutch switches, ...
First you need to troubleshoot the 1994 LeSabre cruise control. Check the fuse, the cruise switch, the linkage, to find where the problem is. Check the vacuum lines on the engine as a vacuum leak can cause the cruise to not work properly.
The cruise control operates on vacuum. There is a vacuum canister somewhere underneath the battery which sometimes goes bad. Also check vacuum lines for cracks.
The cruise control may not work is there is a problem with the brakes. Check to ensure that the cruise lights come on in the dash. Also, check all the vacuum lines to see if there is any issue.
First step might be checking the vacuum lines in the engine bay. If the cruise control unit does not get vacuum it will not work. Second, the brake light switch might be suspect at that age, it might be sticking or not working. Last, the buttons inside the car or the cruise control unit might have failed.
Check the vacuum lines on the driver side of the engine.
Normally the vacuum line from a brake booster goes to the intake manifold of a gasoline engine. Sometimes other lines will be tied in to feed vacuum to cruise control pots or 4x4 actuators, but the main hose will be larger.
first check the fuse.then check the cylinder under the hood,(which is located between the firewall and the fuel injection system) make sure ,(if there are) vacuum lines going to the cannister for cruise control, check all linkages and vacuum lines involved with fuel injection system and criuse control, for a crack or split or leaking. You may lubricate linkages. hope this helps!
Check the cruise control for the Prelude first. Then check the cruise relay, any linkages, and the vacuum lines. If these are ok, then run a computer code check to see if any codes show up. A code issue could cause the cruise to not operate properly.
Most all of the vacuum lines will start from the intake manifold in the rear..........
Mazdatruckin.com has a schematic for the B2600i vacuum lines in their tech section, it includes 4wd and cruise control devices. See the attached links below.
The first thing you should check are your vacuum lines. If they are old and dried out, they may not be holding a vacuum. If it isn't holding a vacuum, it won't work (or it might work for a short time or your speed might fluctuate up and down when you have the cruise set). Take an old piece of the vacuum hose into any auto parts store and they can get you the correct size. You should be able to replace all of the vacuum lines associated with the cruise control system for under $10.00. You may want to purchase a repair manual - it will make your life much easier whenever you need to work on the car yourself.