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Posted By: soundhd NEED INFO ON CRUISE CONTROL SYSTEM FOR 1978 CHEVY VAN - August 14th 2009 3:01 pm
Just purchased a 1978 Chevy G20 Short wheel base van. Runs great. Cruise control does not seem to work. Has the activation button in the end of the turn signal lever. Trim tag mounted on the inside of hood does not list cruise control (don't know if it is included with a "package" or not. I have a 1972 Olds 442 and I have a cruise control system for that car (have not installed it yet) but it has a on/off switch that mounts on the dash and a control box that mounts unde the hood and a vacume/control diafram that connects to the carb linkage and it moves the linkage back & forth...etc....anyway I am trying ti find out what all is supposed to be installed under the hood for a 1978 chevy van cruise control system so I can check to see if it is all there. Any help will be appreciated. Thanks
The signal lever might have been replaced with a cruise control lever...
Look in the engine compartment for a servo unit(drivers side behind the carb...big bulky thing) or look for a wiring plug long and flat with about 6 ish wires going to it just sitting around...
If you don't have either of these your van is not wired for cruise and an after market one will have to be used or rewire your van with a factory wiring harness out of a van with cruise....
Not worth the hassle...aftermarket ones suck
Here's what should be on the engine if you have factory cruise control. 1st pic is the actuator & 2nd pic is the transducer. There will be 2 speedo cables hooked up to the transducer.
There will also be a vacuum switch under the dash near the brake pedal arm. Hope this helps. Brad [Linked Image] [Linked Image]
Thank for the info. Will take a look at it later this week.
I fixed mine in a 1977 shorty Chevy , had to replace both speedo cable and the transducer , servo was good . You can check the servo by unplugging the vacuum line and holding your finger over the vacuum tube while pushing the carb side of the servo into the servo . If it holds vacuum it’s good . There are no wires to my servo just a vacuum line . The only wires are to the transducer and it is a 2 wire plug in , 3 wire if you have a light in the dash . I found a guy that rebuilds transducers on eBay , they are all the same in Chevy,s so finding one is possible . That’s really where my problem was .
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