John Robinson
Gone but not forgotten
Working on the Cruise Control
Being a stubborn old coot when the cruise quit working it became a challenge to fix it .
The first thing was to check the vacuum and to replace the vacuum check valve.
After several sessions with the vacuum, it became clear that the problem was somewhere else. Now the fun part begins. Using the Field Service Manual diagnostic charts and following the order of troubleshooting in the charts. Everything pointed me at the Servo as being bad however; after buying a new servo and installing it only to not have it work, I decided to go under the dash.
The goal was to check the relay and make sure that the brake dump switch was holding vacuum.
The method used to test the brake dump switch was to put a piece of vacuum hose on the switch and suck on it to create a vacuum. While the switch was holding vacuum pushing the plunger in released the vacuum.
After reassembling the dash, it was time to see if the cruise worked. You guessed it the cruise still did not work. The next step was to check the wiring for the cruise and the cruise switch on the steering column.
The approach was to return the servo, get a new turn signal switch, and just hook it up to the wire under the dash to see if the switch was bad. After switching the old servo for the new, it was time to return the new servo. During the drive the cruise, begin to work with the old servo. The new servo was bad.
You can see the wire from the cruise switch to a connector and then to the turn signal switch. The problem was finally isolated to either the cruise switch or the wires for the cruise.
After a few days during a rain, the cruise quit again. By fiddling with the wires from the cruise switch, it started to work again.
The problem had to be in the switch or the wiring. Again, it was time to go under the dash.
This time the plan was to disconnect the cruise wires from below and gently pull them back up the steering column looking for a skinned spot on the wires. In order to do this you have to remove the bracket that holds the column in place. Now there is a plastic piece that covers the wires coming down the column this is what is holding the wires tight. Remove this plastic piece and reinstall it when done.
After the wires were unplugged, it was discovered that a fine wire could be attached that would allow the wire to be retrieved from the column.
After close examination, the problem became evident and a single wrap of electrical tape repaired the bare spot. Even that was enough to make the wire hang up when pulled back into the column.
I hope this may be helpful to someone else in the future.
None of this would have been possible without the help of GMJunkie it was his ideas that lead me to the right solution.
Thanks Jesse
