I have an 85 iroc converted to carb. I hooked up a TCI tcc lockup switch. I ran the power wire through the brake switch so that the 12v would be interrupted when braking and unlocing the tcc. Everything was working fine and then the tcc quit locking up in 4th gear. The brake switch wire I tapped into is brown. The other wire on the brake switch is two lead grey. The grey used to get constant 12v and the brown would when the brake petal is not depressed. Where does this grey wire get power from? The grey and brown wires do not turn on the brake lights. Those wires are orange and blue and are working properly. I need to know what the grey and brown wires control. The cruise maybe. The brown and grey wires are normally closed circut and open when the brake pedal is depressed, hence unlocking the tcc. The blue and orange are NO and then NC when the brake pedal is depressed, hence turning on the rear brake lamps. So I have to tie into the brown wire. What do they do and where does the grey wire receive power from. I checked all the fuses and their good.

 

so no one has any ideas?

 

Yup.


According to GM manual, it's the Gauge fuse. But I can't guarantee it's true.

Lou

 

I thought cruise but don't know why I don't get power to the gery wire(s) anymore. All my fuses are good. I will try to search down an open in the grey circut.

 

Figured it out. The grey wire(s) on the brake light switch get 12v when the cruise control in set to on at the column stem. This works out because it is a manual override "off" if something occures to the tcc circut. Hope this helps someone else out.