Hello there!
I have a 1988 V10 Chevy Suburban. I have went though all the vacuum checks, along with replacing the cruise control switchat the pedal. It was bad. We have tracked down a wiring issue. It seems the brown wine going to the cruise control .odile is pulsing 1.2 volts positive, to negative, back and forth. Therefore we are thinking there is no.way for the cruise to lock
In. Any ideas what could be causing this? I wouldn't think this was normal.