Simmsled

This is how to fix your cruise control vacuum switches safely, easily, and for about $8. This applies to every single 80/90 model with cruise.

If your cruise control vacuum switches are leaking air (very likely if they are original), it is because of a worn out o-ring seal. A vacuum test will verify if they are leaking or not.

Required tools/materials:

*Small flat head screwdriver or sturdy knife
*One sewing needle
*A very small amount of silicone lube or moly grease
*Autozone Value Pack O-Ring kit (Dorman 799-450) You will need one o-ring out of this kit per switch. Use the following part: (5mm ID x 9mm OD x 2mm W)


Step 1: Remove the switches from the vehicle and you will have what you see below.


Step 2: Gently pry up the tabs to get the top and bottom separated. ***Be careful not to lose all the pieces when you get the top off as there is a small compressed spring inside.


Step 3: Separate the top from the bottom and get your needle in the bottom half to remove the gray o-ring. Mine came out no problem.


Step 4: Install your new o-ring by pressing it into the place the old one was. You can use the blunt end of a pen or the eraser end of a pencil to seat it. Put a bit of lube/grease on the plastic end that will slide down there and snap it all back together. Run another vacuum test and voila! No need to get new cruise control vacuum switches!!!

dragon-ryder

Nice and simple write-up, thanks

93_Audi_90CS

Where is the switch located?

My cruise works....then it sguts down...then it works....then it shuts down...etc.. Really intermittent problem. This sounds like a viable reason for it.

Black Vengeance

They're mounted to the brake and clutch pedals. They 'provide' a vacuum leak when either pedal is depressed to disengage the cruise control actuator.

Simmsled

My cruise control would turn on, then I would just gradually lose speed. I figured it was a vacuum leak since the system would still try to work (the vacuum motor was trying to keep vacuum and was operating). After checking all of my hoses, I figured it would have to be the switches. Sure enough. I looked at worldimpex.com and saw that these switches are on nearly everything VAG from 1979-1999, and a few cars to 2002. Amazing.

Audicted

Nice write up. One more spring project.

4AudiQ

My cruise works intermitingly.
Where do I find these switches?
How many?

Simmsled

They are right above your feet in the foot well. The brake (and clutch for manual cars) pedal(s) rest against these switches. You'd have to take the panel in front of the drivers knees out to gain access.

Manual cars have 2

Automatic cars have 1

(one switch per)

cuatrokoop

Nice!! I need to check the bits on the A6 and V8 actually...