Cruise control quit working

[RedTDIowner]

I drove my 2002 Jetta TDI off the show room floor 19 years ago. For over 350,000 miles my cruise control has worked fine but yesterday all of the sudden it will no longer work. The only time I could never get it to work was when the brake light switch broke but when that happens there would be a light come up on the dash and that is not happening this time. The cruise light on the tachometer is still lit up but I can't figure out why I can no longer set the cruise. I have turned the cruise switch on the turn signal off and on plus I even turned off and restarted the engine but still can't get it to work. Any ideas? Thanks in advance for your help!

 

[irvingj]

On my 2005, I had the same thing... sort of. No warning lights indicating cruise was out ("CRUISE" indicator would still light up), no CEL, nothing -- but the cruise wouldn't work, couldn't be "SET." There are several switches involved in allowing the cruise to work, and I had checked pretty much all of them, even taking apart the stalk switch to clean & lube that. Incidentally, and for about $150, dealer had said all switches were working as they were supposed to.

That's when I decided to invest in Vag-Com software for myself. This was back in 2009.

Turned out to be a broken switch on the clutch pedal. One of the teensy blades on the internal contact set had cracked, eventually shifted over and lost electrical connection. $20 part, but be very careful putting it in, if that's the issue (be sure to read about clutch switch warnings & how to properly install). On my VAG-COM, that switch would not indicate a change from zero to one (or vice-versa), indicating it wasn't working.

Although the dealer still insisted that wasn't the issue when I ordered it, the new switch solved the problem.

I took the broken switch in to the dealer to show their service guy.

 

[RedTDIowner]

Turned out to be a broken switch on the clutch pedal. One of the teensy blades on the internal contact set had cracked, eventually shifted over and lost electrical connection. $20 part, but be very careful putting it in, if that's the issue (be sure to read about clutch switch warnings & how to properly install). On my VAG-COM, that switch would not indicate a change from zero to one (or vice-versa), indicating it wasn't working. Although the dealer still insisted that wasn't the issue when I ordered it, the new switch solved the problem.

Thanks for taking the time to reply in detail. Do you have a link you can share with me about how to properly install the clutch switch? Is it safe to assume the problem couldn't be a fuse since the cruise light is lit up on my dash? Now isn't your 2005 an A5 and if so is the clutch switch the same on both the A4 & the A5?

 

[Nuje]

If you have VCDS (or similar), you can test the cruise switch function in 01-Engine / Measuring Block 6.

Got this from a member (I think it was Nero Morg) here:

If the cruise is still not working, you might have an issue with your clutch and/or brake switch. You can check the operation of those under the Engine controller, Measuring Blocks, and Group 006 Third box for Cruise Control system, it should read "000011" which will indicate it's ready to set cruise.
Here's a brief breakdown of what that readout means"
* x00011 - Indicates if clutch is depressed or not. Zero means released, 1 means pressed
* 0x0011 - Indicates if Brake pedal is depressed. Again, zero released 1 pressed.
* 00x011 - indicator for Resume (+) switch, will stay zero by default, will switch to 1 when button is pressed, when released goes back to zero.
* 000x11 - indicator for Set(-) switch, operates the same as Resume
* 0000x1 - indicator for Cancel switch, pressing it changes it to a zero, releasing changes to a 1
* Turning off the stalk switch changes all digits to a zero, and the Cruise control 4th box will change from 1.0 to 0.0.

 

[benmarks]

A 2005 can still be a MK4. You'll usually see a MK5 2005 described as 2005.5.

I had something similar happen on my car too, but it turned out to be related to an ABS sensor. Everything seemed normal and all the lights lighted up, but cruise control wouldn't work. It turned out a local parts reseller had sold me two sensors whose part numbers matched, but whose manufacturers did not match. After swapping one of the sensors with one that matched the other, the issue went away. Just one other thing to keep in mind.

 

[Nuje]

Post #2 in this thread from Vortex has a pretty good how-to on installing the cruise switch without breaking it.

 

[snakeye]

Try activating cruise control while signaling, see if that works.

 

[RedTDIowner]

Try activating cruise control while signaling, see if that works.

Well my car still will not start if the clutch is not pressed to the floor so the clutch sensor appears to be working correctly. Next I will try to set the cruise when I have the turn signal on.

 

[Nero Morg]

There's two clutch switches. One is strictly for start interlock, the other is for cruise.

 

[RedTDIowner]

There's two clutch switches. One is strictly for start interlock, the other is for cruise.

Ok well, while driving down the road I put on my turn signals and then tried to set the cruise but it still would not work. I am assuming there is no fuse that could be out since the cruise light on my tachometer is lit up so I guess the next step would be to replace the clutch pedal switch?

 

[BobnOH]

Next step is to diagnose the system, there are several things that will cause the cruise to not work. VCDS would be very helpful, though you can do quite a bit with a multi meter. Our cars are getting older and we're seeing a lot of issues caused by bad wires/connects.
VW TDI Search Engine

 

[Nero Morg]

Do you have access to VCDS? It'll be a lot easier to diagnose instead of shotgun repairing it.

 

[RedTDIowner]

What is a VCDS? I bet my mechanic has one.

 

[Nero Morg]

Ross-Tech: Bentley CD Order Form

If he has VCDS it'll be a lot easier to try and figure out. You can literally actuate each switch for cruise control and see if one isn't registering with VCDS.

 

[irvingj]

What Nero Morg said -- I know there are definitely two brake switches, and I'm pretty sure there are also two on the clutch: one for the starter-interlock and a second one for disengaging the cruise control. Senior moment -- I don't remember for sure....

I believe it was on this forum that I found the link about how to install a new clutch switch without breaking it -- the link above is probably it. You'll have to remove the plastic panel below the instrument panel to see the switch(es), but that's not very involved.

One thing to keep in mind about that clutch switch: I was very surprised to find it's a normally-closed (NC) switch, but is HELD OPEN when the clutch pedal is in is NORMAL position, i.e., your foot is OFF it.

Now stop and think about that: what percent of the time is that switch blade being pulled back to keep it open (your foot OFF the clutch pedal) -- 90%, 99%, 99.9%? That's a bunch of stress on that switch blade, ALL THE TIME, essentially. No wonder mine broke. Seems like VW could have devised a different set-up, either a NO (normally OPEN) switch, or perhaps a photoelectric switch.

Maybe that's not the problem with your car, but I was flabbergasted to see the way mine --and probably yours-- was designed.

And BTW, as benmarks pointed out, mine is a 2005, but most definitely an A4 chassis, one of the last diesel (PD/BEW) engined-Jettas VW sold prior to the BRM common-rail engines. The (IMHO) rather un-attractctive 2005.5 model (the ones with the huge chrome "smile" on the front) was the last --and only a few at that-- of the Jettas to have the PD engine, before diesel sales were suspended so they could "perfect" the BRM engine.

Check that clutch switch!

 

[jimbote]

What Nero Morg said -- I know there are definitely two brake switches, and I'm pretty sure there are also two on the clutch: one for the starter-interlock and a second one for disengaging the cruise control. Senior moment -- I don't remember for sure....

I believe it was on this forum that I found the link about how to install a new clutch switch without breaking it -- the link above is probably it. You'll have to remove the plastic panel below the instrument panel to see the switch(es), but that's not very involved.

One thing to keep in mind about that clutch switch: I was very surprised to find it's a normally-closed (NC) switch, but is HELD OPEN when the clutch pedal is in is NORMAL position, i.e., your foot is OFF it.

Now stop and think about that: what percent of the time is that switch blade being pulled back to keep it open (your foot OFF the clutch pedal) -- 90%, 99%, 99.9%? That's a bunch of stress on that switch blade, ALL THE TIME, essentially. No wonder mine broke. Seems like VW could have devised a different set-up, either a NO (normally OPEN) switch, or perhaps a photoelectric switch.

Maybe that's not the problem with your car, but I was flabbergasted to see the way mine --and probably yours-- was designed.

And BTW, as benmarks pointed out, mine is a 2005, but most definitely an A4 chassis, one of the last diesel (PD/BEW) engined-Jettas VW sold prior to the BRM common-rail engines. The (IMHO) rather un-attractctive 2005.5 model (the ones with the huge chrome "smile" on the front) was the last --and only a few at that-- of the Jettas to have the PD engine, before diesel sales were suspended so they could "perfect" the BRM engine.

Check that clutch switch!

your broken switch is definitely an outlier. I've only seen one or two fail from normal use in many years of working on these. I have seen quite a few fail from ham fisted install or removal though.

 

[irvingj]

Well, coulda been. I have to admit I haven't heard of a lot of those clutch switches failing on their own, but I do believe the basic design by VW could have been better.

And I have to admit, I'm still a bit pissed that it cost me well over $100 for the dealer to tell me "all the switches are OK", only to find that they weren't, after I connected my own newly-purchased Vag-Com software.

Yeah, it could have been a momentary "works OK" situation while at the dealer, an intermittent problem... and perhaps the money I gave to the dealer (GRRR!) is influencing my opinions.... but it still struck me as odd that a switch would "normally" sit in it's exercised --mechanically stressed-- position. In any case, something to look at.

Thanks for your input, jimbote. Sounds like you have a lot more experience than I. (I prefer to play with 70s Japanese motorcycles....)

 

[RedTDIowner]

And I have to admit, I'm still a bit pissed that it cost me well over $100 for the dealer to tell me "all the switches are OK", only to find that they weren't, after I connected my own newly-purchased Vag-Com software.

Well I see the Vag-Com software costs $99. What else do I need? Just a plug to connect to my computer?

 

[Nero Morg]

If you get just a dummy cable, you can use VCDS lite which has a trial free version. The KKL cables vary, but are usually like $20.

 

[Nevada_TDI]

Help! I am so grateful this thread has been updated. A couple of years ago my clutch switch died and I had no cruise, so I replaced the "blue" switch, and all was well. A while back 6 or 10 months anyway. The cruise started getting flaky: sometimes I hit the switch and the cruise would work until I hit the brake, and then sometimes the resume did not work, and some times resume would work then stop working and not work at all. So I sprayed inside the stalk area, and the cruise worked on and off for a couple of days. Tonight I went to the car, plugged in VCDS and checked all of the switches, and the switches all checked out: 1 when pressed, 0 when released. I did notice something odd, when I depressed any one of the switches the far right box changed from 1.0 to 17.0, any clues on what might be the problem? And not that it matters my Cruise Control indicator never worked.