1993 Cruise control vacuum line

[Robert252]

Originally Posted by ChevyTech

The most probable cause is the brake switch.
The brake switch is a high failure parts on these trucks.
If the switch was out of adjustment is could cause the problem.

For C/K trucks 1988 to 1993

Here is how the switch is adjusted:
On the curved side of the switch, which is pointing down and somewhat towards the front of the vehicle when installed, the end of a lever protrudes slightly out of a slot.
While holding the brake pedal down a little ways, slide the lever that protrudes from the slot toward the driver’s seat.
Let go of the lever, and then return the brake pedal to its fully released position, and the switch should self adjust.

Brake Switch mounting – Installing:
The body of the brake switch should not move with the pedal at all. Remove the switch and install it again. When you have the switch removed look at the side of the switch that would be towards the parking brake pedal if the switch were still installed. There is a protrusion on the switch that must slide into an opening where the switch mounts. Somewhat like a big square lug into a slot.


The RWAL (Rear Wheel Anti Lock) is setting a code 10.

Code 10 indicates problem with the brake switch at the brake pedal or the circuit for it.
It is common for the brake switch to go bad on these trucks.
Check and see if your brake lights work, but even if the brake lights work ok there could still be a problem with the brake switch because it has multiple contacts for multiple circuits through it.
The self test for code 10 happens when the vehicle reaches 35 MPH.

Thanks for the info I will adjust the switch. The switch that is in there looks pretty new.
Are you saying that if the switch is out of adjustment the power wont go to the brown wire? The brake lights work ok.