Confusion with brake pedal and cruise control

[Danny_oy]

Hello, just looking for a little help here. Currently diagnosing a no cruise control and feeling a little defeated.

I've read on many forums that you can measure cruise control devices using the vagcom to find out what is giving you trouble, and have found that under measuring block 06, the middle section reads 001 instead of 000, which indicated that my brake light switch is bad. I've replaced the switch and have led brake lights that work none the less. What would someone more experience than me recommend replacing first, getting OEM bulbs or getting the upgraded switch that's not from a big box parts store?

 

[Nuje]

There's a process to locking the brake switch into place - can't remember exactly what it is, but check out youtube as I'm sure there'll be at least a couple decent how-to there.

If I don't have time to place an order with them, I'll typically take a look at the brands that idparts.com and cascadegerman.com sell, and if local parts store has that brand, I'll feel comfortable with them. If it's like URO or some other brand that often shows up on Amazon....pass.

 

[Vince Waldon]

The brake switch has two internal circuits, one for the brake lights and one for the cruise control.

If VCDS says one side is stuck regardless of petal position, and you've replaced the switch, then a wiring issue is your next suspect

 

[Alchemist]

The ECU is connected to both sections of the brake light switch, and compares them to see if the brakes are on, bulbs are burnt out or the switch is defective.

The section that supplies power to the lamps is effectively grounded through the lamps when they are off. If you have LED brake lights, they do not have a low enough resistance to act as a ground connection. The ECU will then not see the ground it is looking for and not enable cruise because it thinks there is something wrong with the brake light switch.

Do you have load resistors in the brake light circuit? If not, put the regular incandescent lamps back in and you should have cruise working.

 

[J_dude]

Like @Alchemist says, this is most likely a LED bulb issue. You can put resistors in, but I personally don't like that approach. As an alternative, there is a way to wire a relay in the brake circuit such that the ECU will see a ground when it expects to and so won't think a bulb is out.

 

[Danny_oy]

Like @Alchemist says, this is most likely a LED bulb issue. You can put resistors in, but I personally don't like that approach. As an alternative, there is a way to wire a relay in the brake circuit such that the ECU will see a ground when it expects to and so won't think a bulb is out.

I've done more research into it and this is most Definitely the issue. it will start out good but once I press the breaks and turn on cruise it instantly defaults to 001. the idiot before me wiring in a trailer light harness directly into the wiring harness so I've made quick work of removing that. is there any way you could find me a diagram for that relay?

 

[J_dude]

I've done more research into it and this is most Definitely the issue. it will start out good but once I press the breaks and turn on cruise it instantly defaults to 001. the idiot before me wiring in a trailer light harness directly into the wiring harness so I've made quick work of removing that. is there any way you could find me a diagram for that relay?

I thought it was in this thread but I'm not seeing it, I'll keep looking.

Edit: HERE it is! Post #17:

LED Brake Light Bulbs that Won't Give Error?

Hi Guys, Does anyone know of any 1156 LED that are currently on the market that won't give an error when used as brake light bulbs? Thanks, Pat

forums.tdiclub.com

 

[Danny_oy]

I thought it was in this thread but I'm not seeing it, I'll keep looking.

Edit: HERE it is! Post #17:

LED Brake Light Bulbs that Won't Give Error?

Hi Guys, Does anyone know of any 1156 LED that are currently on the market that won't give an error when used as brake light bulbs? Thanks, Pat

forums.tdiclub.com

Thank you so much man, you're a real lifesaver!

 

[Danny_oy]

update for anyone that might find this thread later. the 001 code block in the middle of 06 cruise control in measuring blocks of engine module will fault for brake LIGHTS, not brake switch. 010 is a fault for the switch, 001 is a fault for the lights. if you hover the mouse over the measuring blocks readings it will tell you what numbers mean aswell. the relay helped fix the cruise problem and fixed my lighting issues. ****ty diagram of relay path below

http://imgur.com/a/T0eYRDg