Cruise control switch broken/reversed?

[Castor Troy]

This is on my 6 speed swapped S6. Problem I've got is that the ECU is seeing the clutch switch position reversed. When the pedal is out, the ECU thinks the pedal is down(verified with VCDS, getting a 1 for 066-2 position 6). When I press the pedal down, the VCDS shows a 0 for 066-2 position 6, meaning the ECU thinks the pedal is up. Because of this, I do not have cruise control. I pulled the switch from the bracket, but left it plugged in. In this condition, VCDS shows a 0 for 066-2 position 6, and cruise control works properly.

I believe that everything is wired properly; I tried both the solid white and the white/red stripped wire off of the brake switch, same results with both. Verified that the other side of the switch is connected to pin 39 on the ECU).

This is what VCDS shows when the clutch switch is installed and the pedal is up. Cruise control does not engage.



This is what VCDS shows when the clutch switch is installed and the pedal is down. It's also what VCDS shows when I let the clutch switch hang. Cruise control engages.



At this point the only two options I can see is that my cruise switch has failed, or that I've spliced into the wrong wire on my brake pedal. Having already spliced into two different wires, I'm hesitant to try the other two unless someone is confident I've wired it up wrong.

[cu52]

I would check functions of the Set/Decel and Resume/Accel on the cruise in box 4 from VCDS. If those work with no issues then I would think you have a wiring issue/switch issue Given that you see CCS switched on for the last two positions it appears the switch is working. Is the CPP switch new?


Image shows White to switch (3) to Red/Green (2) to pin 39. I assume you have done a continuity test from Red/Green to pin 39 on ECU to verify that it is not shorted or broken by your comment above. Wiring diagram (2004 Allroad) shows WS into both switches but separate lines from each switch to different pins on the ECU.

My guess is wiring into/out of switch is reversed.

[Castor Troy]

Switch is working, and with the clutch switch removed(still plugged in but not engaged by the pedal) all cruise control functions operate properly.

It acts like the polarity of the switch is reversed, but since the switch is just opening/closing a circuit, it shouldn't matter which way it is wired, should it?

[Korben007]

Is the switch wired to power or ground

[blitz2190]

This is on my 6 speed swapped S6. Problem I've got is that the ECU is seeing the clutch switch position reversed. When the pedal is out, the ECU thinks the pedal is down(verified with VCDS, getting a 1 for 066-2 position 6). When I press the pedal down, the VCDS shows a 0 for 066-2 position 6, meaning the ECU thinks the pedal is up. Because of this, I do not have cruise control. I pulled the switch from the bracket, but left it plugged in. In this condition, VCDS shows a 0 for 066-2 position 6, and cruise control works properly.

I believe that everything is wired properly; I tried both the solid white and the white/red stripped wire off of the brake switch, same results with both. Verified that the other side of the switch is connected to pin 39 on the ECU).

This is what VCDS shows when the clutch switch is installed and the pedal is up. Cruise control does not engage.



This is what VCDS shows when the clutch switch is installed and the pedal is down. It's also what VCDS shows when I let the clutch switch hang. Cruise control engages.



At this point the only two options I can see is that my cruise switch has failed, or that I've spliced into the wrong wire on my brake pedal. Having already spliced into two different wires, I'm hesitant to try the other two unless someone is confident I've wired it up wrong.

sounds to me like you may have the wrong clutch switch, it could be that you have the one thats meant for the interlock relay and it switches when pressed, its the lower clutch switch, the one meant for the ecu/cruise control is the upper clutch switch and activates when depress(clutch in). what part number is on your switch?

Is the switch wired to power or ground

wiring to ground will do nothing wiring to power will show a change like he had. the ecu has pull down resistors (or up in some cases) that tie the switches to ground in case they fail so it disables the systems they are tied to (cruise control in this case)

[Castor Troy]

sounds to me like you may have the wrong clutch switch, it could be that you have the one thats meant for the interlock relay and it switches when pressed, its the lower clutch switch, the one meant for the ecu/cruise control is the upper clutch switch and activates when depress(clutch in). what part number is on your switch?



wiring to ground will do nothing wiring to power will show a change like he had. the ecu has pull down resistors (or up in some cases) that tie the switches to ground in case they fail so it disables the systems they are tied to (cruise control in this case)

lol. you figured it out. guy who did my swap wired the interlock/starter switch to the ecu, and didnt even install the other switch.

can someone tell me where the fuck the actual clutch switch is supposed to go, and what p/n it is??

[rollerton]

The switch you have looks correct from what I can see? Does it have 4 pins or 2?
The clutch 'safety' switch is the one that's wired to the starter interlock relay. It's supposed to be up higher on the pedal assembly bracket over on the right hand side kind of above the brake pedal.
The clutch position switch is the one you're working with; you can test the switch is correct with an ohm-meter. That switch is 'normal closed' meaning it OPENS the circuit (=current doesn't flow through when pressed) from brake switch when you press the clutch.
If you want to be 100% sure you have it wired correctly simply use a test light and test for 12V power that goes through the brake switch TO the tail lights when the brake is pressed. That wire I believe is black/red ?
Here's how the ECU clutch/brake logic works: Since the clutch switch is a 'normal closed' the ECU knows the combination of brake /clutch pedal action because when you press the brakes but DON'T press the clutch 12V comes from the brake switch through the clutch switch to pin 39. If you press the clutch then the circuit 'opens' and 12V no longer is seen at pin 39. The ECU always knows the position of the brake pedal, and wired this way it knows the position of the clutch pedal.


The clutch safety switch is the opposite, it 'closes' a circuit when pressed and grounds the interlock relay to start the car. In a pinch you can use a spare brake switch to do the functions of BOTH the clutch 'position' switch and the clutch safety switch, it has 4 wires and has two 'switches' inside one is normal open and one normal closed.

[Korben007]

Double check that's not a brake switch. They look exactly the same but function opposite like you discribing. The brake switch with break the connection when the pedal is up. And provide continuity when the pedal is depressed. A clutch switch does the opposite. Looks completely identical on the outside. Ask how I know lol

[Castor Troy]

Double check that's not a brake switch. They look exactly the same but function opposite like you discribing. The brake switch with break the connection when the pedal is up. And provide continuity when the pedal is depressed. A clutch switch does the opposite. Looks completely identical on the outside. Ask how I know lol

the p/n is for the the brake switch. need the clutch switch p/n if someone has it

[Korben007]

Looks like you found your problem then

[Korben007]

Just look up a clutch switch for in Allroad or a manual A6 and you should be good

[Castor Troy]

the only one i'm really finding listed is advertised as the starter safety switch. is that the right one?

https://www.amazon.com/Standard-Moto.../dp/B005UW17UK

[rollerton]

the only one i'm really finding listed is advertised as the starter safety switch. is that the right one?

https://www.amazon.com/Standard-Moto.../dp/B005UW17UK

That is WRONG. That ^ is the clutch position switch.

This is the clutch safety switch, it sits on a little bracket more up and above the brake pedal.

https://www.ecstuning.com/b-genuine-...MaAgtNEALw_wcB

If you don't have the right switch and would like to use a brake switch to do both functions I have an extra one I can send you. And I can tell you how to wire it up. I just did the whole pedal assembly thing the other day in my S6.

[Castor Troy]

All I want is for the cruise control/ecu switch. I already have the starter switch bypassed

[rollerton]

All I want is for the cruise control/ecu switch. I already have the starter switch bypassed

Ok, well that switch you have *looks* like the right one. You should test it and make sure that the circuit is -closed- normally and opens when you click it down. (meaning 12V goes thru it untill you press the clutch).
And I have a brake switch you can use in place of it if somehow that's the wrong switch. And you could use to to run the clutch safety relay at the same time- because the correct clutch safety switch is fucking expensive.

[swlN7]

I had the same issue with my switch after my swap. I ended up using a relay to switch the signal.

[Castor Troy]

Update. Confirmed the part number on the switch I was sent is 443945515, which is a brake switch and opens/closes the opposite of the clutch switch. After a lot of searching, I finally found the P/N for the correct switch, which is 8D0911807A. Local dealer ordered it for me and I'll hopefully have it thursday to be sure that my issue is finally resolved

[Korben007]

I went through the exact same thing on I went through the exact same thing on mine. Those pesky identical brake switches

[blitz2190]

also to answer you other question that switch is in the right place just the wrong switch, now that you have it figured out its a quick switch.

[Castor Troy]

Got my new switch installed, car is now 100%. Thanks for the help everyone