1984 - 1989 Cruise Control Repair Guide

by Bryan A. Thompson

Last Updated 11/25/2001

Note:  I haven't had time to update the site with this info yet.  For now, know that:

1)  The factory Cruise Control electronics for 84-89 Vettes are contained in the Digital Cluster.

2)  A user tip from Bob Golden:

"The cruise control driver transistor P/N was 16008121, a number I came all too familiar with.  Almost every time you find the transistor open in the cruise circuit, you can bet the solenoid valve in the servo is burned. This holds true with 
almost all vacuum controlled GM cruise modules. If the level wiring 
shorts it usually just blows a fuse. We didn't see too many problems 
with the cruise circuits until these cars bean to age and the servos 
begin to intermittingly short. If you catch it in time you can save the 
circuit by changing the servo out. These servos are expensive but a lot 
less than a cluster repair. I never had much faith in the rebuilt 
servos, they tend to surge. You can find the new ones at a better 
price if you buy from a AC-Delco distributor. They range from $110 to 
$150. This is way over priced but that's how it is."

3)  Click Here for a set of schematics on the Cruise Control board integrated into the Digital Cluster.

4)  The most common reason that Cruise won't set is the TCC kickdown switch located above the brake pedal.  It slides away from the brake pedal quite easily.  The Cruise electronics think the brakes are applied and won't engage the cruise.

5)  Click here for a list of known problems with the cruise control associated with the digital cluster.

 

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