1977vetteguy

Does anybody know why the cruise control on a 1977 vette would not work? I have heard that it could be vacuum issues. If anybody has ideas please let me know. Thanks

gbvette62

Your problem is most likely with the transducer. The transducer controls the functions of the cruise control. The transducer is activated by electronics and then controls the system by vacuum. The transducer is mounted below the master cylinder, it has the upper and lower speedometer cables running to it. Transducers are available from most Corvette vendors. Rebuilt 77-80, 2 wire transducers, sell for about $150.00.

Beyond the transducer, it could be a vacuum line or leak, it could be the switch in the stalk, a wiring problem, or even a problem with the brake light switch. I would check these out first, and if all are correctly connected and functioning properly, than I would replace the transducer. A GM shop manual will give you trouble shooting tips, if you have one, or access one.

Seasoned80

If your speedometer works, the problem is probably not the transducer.

7T1vette

First thing to check is the fuse that protects it. Then check that the vacuum lines and electrical running to it are functional. If your speedo works, then the cable running to it is turning and the cruise transducer is getting the 'speed' signal it needs. Otherwise, the speedo cable or tranny cable drive gear could be defective. The control switch/wiring on the steering column could be defective, too.

If you have vacuum, voltage, activation signal and speedo signal getting to the transducer and it still doesn't work, remove it, disassemble and clean it, then try it again. If no joy, buy a new control head.

larryg3

RonR80

check out our CCC site I just wrote an article on the cruise, Ron' tidbits capitalcorvetteclub.ca this one is on my car an 80 let us know how you make out! Ron