Adding cruise control?

Hi All --

I have two caprices -- an 87 and an 89, both 9C1s. I'm wondering how hard it would be to add cruise control to one or both. (one is carbureted, the other is TBI -- not sure if that makes a difference)

Neither car had CC as a factory option, but curious of the cars have the wiring harness anyway. If so, what are the steps and parts one needs to add? (presumably the turn signal lever and the CC module itself -- anything else?)

If they don't have the necessary wiring, how much of a chore would it be to add it?

thanks.

Factory cruise control units tapped the VSS signal from the VSS buffer box and used that for a vehicle speed reference. The factory installations required an additional brake pedal switch to break the holding circuit for the cruise when the brake was applied. The 1987 model also used a ported vacuum valve on the brake pedal as a redundant safety device to release the vacuum in the cruise servo when the brake pedal was depressed.

Aftermarket units will have everything you would need for a successful installation. Retrofitting an OEM setup will be quite a chore, and the wiring will not likely be present in the harness.