I need help troubleshooting the cruise on my 87 gn. The cruise does not work at all and the cruise light does not come on. I have checked the following. With the ignition on and the cruise button in the on position, when you depress the set button an audible click can be heard at the cruise servo. The cable moves freely. There is vacuum going to the cruise unit and it holds vacuum so I assume the diaphram is good. I checked the larger vacuum hose which goes to the brake pedal, the hose is not leaking and the valve works correctly. The fuse is not blown and there are no trouble codes stored. Any help would be appreciated
Take a quick look at the brake switch/wiring to it. I believe when you depress the brake pedal when in cruise, it opens the connection and will shut off the cruise control. If it is always open, it will not come on. Also, is the lamp good? One more thing, don't go by the brake light for the brake switch's continuity-I've seen it where the brake lights work, but the cruise doesn't.
Dale
I believe there may be two switches activated by the brake pedal when depressed, bottom one for the taillights and the top one for cruise. Took me awhile to figure that out, but that was the problem, just needed to adjust my switch and cruise suddenly worked.Hope that helps
Scott 87 GN Wisconsin
I think I had the brake pedal problem once also...
Also, what about the VSS or vehicle speed sensor? Are you sure you are not getting any codes?
Thanks for all of the input guys, I will look at it when it comes out of the body shop and let you know what I found.
I have had simular problems too. I work at a GM dealer and the number one part I sell for cruise control is the switch/lever. In my experience if your bulb is good but does not light it is the lever. Its hard to diagnose with out the shop manual but if I had to guess thats what I would replace. The clicking at the servo might be just the switch momentarally engaging.
Thanks for the tip on the brake pedal switch. My cruise control hasn't worked for about five years and I never had it fixed because I was told it was potentially very expensive to track the problem down. It was the switch being out of position and now it works fine.
I have a 1986 t-type. I'm having electrical problems with the dimmer switch. Every time the headlights are turned on the panel lights goes out. Can anyone help me with this. I love these cars!!!