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C3 78 speedometer cable/cruise

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Old Feb 28, 2014 | 07:36 PM
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Default C3 78 speedometer cable/cruise

I am attempting to install cruise control in a car that did not have it.
I received the speed o meter cables for the cruise control set up. While attempting to install the upper cable I found it was way too short, routing it through the old cable opening. The AIM shows it going straight through the fire wall next to the master cylinder booster. BUT I do not see any place it would fit.

does any one know where to run this cable, or pic's of the location.

upper cable came in a bag tagged with two different number's, one said 68-82 upper cable w/cruise...The other said 64-77 speed- o-meter/tach cable.

By chance, are they the length??? cause I am really short with this one.
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Old Feb 28, 2014 | 07:57 PM
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Originally Posted by Douglas Brown
By chance, are they the length??? cause I am really short with this one.
According to the GM parts catalog the upper speedo cable for 77 to 82 with cruise should be 525mm (20.67 inches) long.
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Old Feb 28, 2014 | 08:04 PM
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Originally Posted by Pete79L82
According to the GM parts catalog the upper speedo cable for 77 to 82 with cruise should be 525mm (20.67 inches) long.
Thanks I'll check that out. I think they came from Ecklers by looks out lable
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Old Mar 1, 2014 | 05:11 PM
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Originally Posted by Douglas Brown
Thanks I'll check that out. I think they came from Ecklers by looks out lable
Measured cable, it is about 24" long...

Now where do I drill a hole for the cable??? next to the fuse block, to of the fuse block?????
May be top so it runs next to the lower dash area and a long the steering column brace.
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Old Mar 2, 2014 | 01:35 PM
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You shouldn't have to drill a hole.

Look for a rubber grommet with ~3/8-1/2" hole in the center, that's where the speedo cable goes through.

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Old Mar 2, 2014 | 05:45 PM
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Originally Posted by Shark Racer
You shouldn't have to drill a hole.

Look for a rubber grommet with ~3/8-1/2" hole in the center, that's where the speedo cable goes through.


Thanks Shark Racer.. As you can see there is not rubber grommet, I will have to drill one, I spent the day researching the AIM and taking photo's.
Yours answered a big question. that rubber grommet you show is like the one where the old speed-o-cable when out next to the throttle, I'll have move it. The car never had cruise or A/C all though there is indication of power window at one time, NO alarm system but wiring for it. Thanks for the help, I did not want to start cutting until I was sure of where it went...


Last edited by Douglas Brown; Mar 2, 2014 at 06:01 PM.
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Old Mar 7, 2014 | 12:57 PM
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Thanks for the pic Shark Racer, Helped out a lot, got the hole cut, grommet installed and transducer arrived, started hooking up the CC harness, attached rubber hose to vacuum valve and electrical connecter to brake switch, hooked other end of electrical to transducer, connecter from un-dash harness to brake light switch. BUT there is a two prong flat connection from the harness by the transducer, one side is black w/ eyelet for ground, What does the other 1/2 of the connecter go to???
Remember this was a car with no CC, could this be for brake switch connection ??

Looked at a harness on lectric limited site, I see an inline connection that attaches to the brake light lead off the harness.
I think that is right??

Nice to guys to talk to.

Last edited by Douglas Brown; Mar 7, 2014 at 01:15 PM.
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Old Mar 7, 2014 | 09:52 PM
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There's a connector that goes to the brake light switch and a connector that goes to the cruise control switch on the stock. That's the only two I can think of.
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Old Mar 8, 2014 | 10:24 AM
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Originally Posted by Shark Racer
There's a connector that goes to the brake light switch and a connector that goes to the cruise control switch on the stock. That's the only two I can think of.
Your right, The CC harness I got was from Corvette Generation, would appear to have come off a car with an up graded brake proportion vale that has a two prong brake light
switch on it, instead of the stock type I have. I will have to splice into the stock brake light wire, to connect the two.

thanks for the info.
DB
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Old Mar 9, 2014 | 06:00 PM
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These are the two brake light wires that need to be spliced together to connect the brake peddle switch, cruise control and brake proportion valve together.


once spliced together attach to brake proportion valve.


And now to hookup the vacuum lines, install washer bottle, Brake master cylinder and steering column.
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