Clutch switch for cruise control

I feel like this ought to go in "TDI maintenance," but I can't seem to find that forum (except in the archived FAQ area).

Anyway, I discovered the other day that my cruise control doesn't disengage when I push in the clutch pedal. How do I troubleshoot and fix this?

While it may be a wiring issue, chances are you need a new clutch switch.

You buy one and replace it. There is one kind that is tricky (but not hard - you just have to know the secret twist) to install without destroying some tender internals, and apparently another that is easy to install. NukeSkywalker just recently replaced his - twice.

You might PM him. He may make it to the GTG, and he may not.

Dan

Use VCDS to check the clutch vacuum vent valve F36 sensor. Measuring block 006. There are two switches on the pedal. One for the starter, and the other for the ECM. The lower one should be the F36 switch.

I have one of the newer green brake light switches as my clutch switch. Much cheaper and its a easy mod. Maybe I should do a write up on it... Hmmmm

Would anyone care to share?

Anyone want to share what the "secret twist" is with installing this. I read something about setting the length, but nothing on how to set the length.

DanG144 said:

While it may be a wiring issue, chances are you need a new clutch switch.

You buy one and replace it. There is one kind that is tricky (but not hard - you just have to know the secret twist) to install without destroying some tender internals, and apparently another that is easy to install. NukeSkywalker just recently replaced his - twice.

You might PM him. He may make it to the GTG, and he may not.

Dan

Click to expand...

How to replace a brake or clutch switch

How to replace a brake or clutch switch.

This is simply a pdf of a copy I had made of a thread. I deserve no credit for it, (or blame). Just displaying it in a different format. If this is improper, someone please let me know.

Dan

Might's well post here... Have a similar problem with cruise: when switched on, "CRUISE" light on dash comes on, but no throttle engagement occurs when rocker switch on the end of the multi-function switch is pushed. Cruise had been operating normally prior to this.

Have checked all brake light bulbs, fuse #5, brake switch (as far as brake lights), and clutch interlock operates normally in that starter will not engage until clutch is depressed. Took it to dealer today as I do not yet have easy access to VAG-COM.

Dealer said that everything checked out OK, but they wanted to replace the brake switch, as it had never been done. I never got a recall notice, and it has always been OK, but I said go ahead. After replacing brake switch, still no definitive diagnosis: their computer indicated all components were doing their job properly ("ALL OK/ VERIFIED COMP CODING"), and that the signal was both arriving at and leaving the ECM, but never reaching, apparently, the throttle control motor ("WIRING FROM SWITCH TO ECM EITHER BROKEN OR CORRODED").

They admitted that further testing of all wiring would be prohibitively expensive for them to do, so I guess I'll try to track down the suspected "corroded wire junction/plug" somewhere in the line, which is what the dealership repair people feel is going on.

Any suggestions or tips before I start tearing things apart? Thanks- WBB in NH/irvingj

irvingj said:

their computer indicated all components were doing their job properly ("ALL OK/ VERIFIED COMP CODING"), and that the signal was both arriving at and leaving the ECM, but never reaching, apparently, the throttle control motor ("WIRING FROM SWITCH TO ECM EITHER BROKEN OR CORRODED").

Click to expand...

I just screwed up editing this, so I'll just retype it...

Admittedly I haven't checked, but since there isn't a actual throttle, there shouldn't be a throttle control motor for the cruise. It's all done in the ECU, isn't it?

Yeah, it's all ECM quantity adjust. All control is purely in the pump/jets and software.

The throttle plate is only used by the EGR.

jcrews said:

Yeah, it's all ECM quantity adjust. All control is purely in the pump/jets and software.

The throttle plate is only used by the EGR.

Click to expand...

that's what I thought.... I wonder how they tested that the signal was leaving the ECU?

Get your money back for whatever 'diagnostic' work they did!

Thanks for the insight-- I have to admit the term "throttle motor" was mine, as I really don't know how fuel is controlled, other than the PD injectors and an electric solenoid.... Ah! Now I see! The ECM simply sends signals to the solenoids (if that's what they are) to control/adjust fuel- the "injector pumps" (PD nozzles) are working 100% of the time, shooting fuel back on the return line if unused...

So-- anyone have an idea of where/how the cruise control signal is getting "lost"? When I originally bought the car (4+yrs ago) they aborted delivery 3 times due to an intermittent check engine light, and ended up replacing what they called the "fuel control computer" --while under warranty, of course. No fault lights now or since....

Sorry for the misuse of terminology- fault is entirely mine. Still learning!!

Thanks!

DanG144 said:

How to replace a brake or clutch switch.

This is simply a pdf of a copy I had made of a thread. I deserve no credit for it, (or blame). Just displaying it in a different format. If this is improper, someone please let me know.

Dan

Click to expand...

That worked great! I can finally stop breaking clutch switches. I have VAG-COM and knew the clutch switch was the issue, but like the PDF says, there's no instructions with the part and doing it the wrong way will break it.

Thanks for saving that post!

One suggestion...

irvingj said:

Thanks for the insight-- I have to admit the term "throttle motor" was mine, as I really don't know how fuel is controlled, other than the PD injectors and an electric solenoid.... Ah! Now I see! The ECM simply sends signals to the solenoids (if that's what they are) to control/adjust fuel- the "injector pumps" (PD nozzles) are working 100% of the time, shooting fuel back on the return line if unused...
So-- anyone have an idea of where/how the cruise control signal is getting "lost"? When I originally bought the car (4+yrs ago) they aborted delivery 3 times due to an intermittent check engine light, and ended up replacing what they called the "fuel control computer" --while under warranty, of course. No fault lights now or since....
Sorry for the misuse of terminology- fault is entirely mine. Still learning!!

Click to expand...

I have no explanation of why this works, but it worked for me. I found that if you unplug and plug in the clutch switch AFTER starting the car, the cruise control will work until you turn the car off.

Since the dealer says everything checks out, I imagine your clutch switch is fine. However, if you try my suggestion and the cruise control starts working, I'd bet its the clutch switch. They cost about $20 and if you follow the instructions posted above, it takes about 5 minutes to install.

You may also try the same thing with the brake switch, since its possible they broke the switch installing it.

I'll try it! (I'll try anything at this point!)

I'll post results after I have a chance to do this.... I'm guessing the bottom panel under the dash needs to be removed for this; did it once, but I must be getting old- will have to figure out how to do it all over again. Never did enjoy "under dash" work, even worse now that I have to wear glasses to see anything closer than 3 feet away....

Thanks for the suggestion, LizardRuss.

clutch switch

No joy. With car running, unplugged clutch switch & tried cruise; did it twice, no change. Tried brake switch, too, but still no go. Did notice one of the "ears" on the plug locking mechanism on the brake switch was broken off.... guess the dealer's people had to fight with it as well.

Now we start digging, but my first priority will be the push button ("set") on the end of the multi-function switch. Again, any suggestions/tips?

I've never had a car with cruise control before, but I have to admit I use it a lot on long trips-- nice to be able to shuffle feet around every now & then. Hate to have to live without it.

multi-function switch/cruise control

Been doing some more reading on the forum--

Anyone know if the "ribbon cable" leading from the switches at the end of the stalk down to the cruise switch body on an 05 wagon might have been superceded with a mylar printed circuit sheet?

Photos I've seen here (great resource!!) show a regular ribbon cable, but I have this gray plastic sheet that's made with a curve on the end, which comes out of the stalk and into a slot on the left of the CC switch body to allow for flexing/movement as turn signal is operated. It has some obvious wear on it. I don't see separate lines on it, but I can't really see the back side of it.

That's as much as I can see before attempting a steering wheel removal.

cruise control inoperative

Well, I'm still hoping for some one to chime in here.... I stopped by the dealer today, and was able to spend a few minutes with the tech who checked my car out last week. He's very sure that all the switches are doing what they're supposed to, showing the proper signal on their (the dealer's) computer hook-up.

He also said he checked all switches (clutch, brake, ON/OFF, Set & RESUME) manually as well as with the computer (?) and everything looked good. He still thinks there's a break somewhere in the wiring that's causing the problem.

I don't have a VAG-COM, but that may not last long.... Any other recent info/experience on an 05 PD Jetta's cruise control?

If the brake and cruise signals are reaching the ECM, it could be that the system is disabled. On the older ECMs, the component name after the part number would contain G, indicating enabled cruise. Login codes could toggle the system on and off. I haven't checked to see if the BEW software works the same way.

I've never checked to see if the measuring blocks remain active when cruise is disabled.

The login code to enable is 11463 (through VAS/VAG-COM/VCDS).

getting VAG-COM

Well, I couln't stand it any longer, so I did some first-class rationalization: I figure having a VAG-COM from Ross-Tech will pay for itself if it saves me only 2.5 visits to the dealer for diagnostics.... so I've ordered it.

jcrews-- thanks; that thought crossed my mind, too, as it would fit the symptoms pretty well. Have to admit my gut feeling was a stalk switch, but the dealer tech was certain.... At any rate, I hope to find out soon.

I'll post results as soon as I have some. I'm planning a long trip this summer, and the CC is a very nice thing to have on such a jaunt; road trips are one of the main reasons I got this TDI. I really don't want to be without CC.

Ross-Tech to the rescue

So the VAG-COM arrived Monday; downloaded software Tuesday; successfully connected to Cruise Control "Group 6" today, afetr re-reading post by Wingnut on flaky CC.

My screen is quite a bit different, which is to be expected, I suppose (newer version?)- but I was sorely disappointed in the rather expensive Bentley manual I bought. It clearly states "Including PD versions" on the cover, but goes no further than the 2002 ALH diesels in both the wiring diagrams and the scan tool section. Hopefully, not too much has changed.

Long & short: all switches changed the 8-digit (not 6-digit any longer, apparently) codes in the "Pedal Monitor" and "Switch Monitoring" sections, except one: The Clutch Switch.

Pushing in the clutch made no changes in ANY of the group 6 blocks. Ah, progress at last! All others did- accelerator pedal, brake pedal, Cruise ON/OFF switch, SET, and RESUME all made changes to the codes (% reading on the accelerator pedal), but not the clutch switch.

Question: the starter interlock works-- i.e., the starter won't engage until the clutch is depressed-- so that part appears to be working; anybody know if that's on separate circuit/switch from the CC's "vacuum vent valve" switch (F36), as it's called in the Bentley book? My assumption was, since the starter interlock worked, the clutch switch was OK-- but perhaps that's a different circuit altogether? (I'll dig through the Bentley book later.)

Yeah, I know-- "assume": makes an a__ out of u and me.... Anybody with BEW experience out there who could save me some time?

Never mind.... Just re-read THIS post from beginning; thanks, jcrews! "Use VCDS to check the clutch vacuum vent valve F36 sensor. Measuring block 006. There are two switches on the pedal. One for the starter, and the other for the ECM. The lower one should be the F36 switch."

Irvingj,

The clutch has two switches. One is when the clutch is pressed in (starter interlock), the other is engaged when the clutch is released. The one at the top is probably your issue. I had the same problem. As far as I know the cruise setup is the same on all the A4s (ALH & BEW).

Bob

screen image

Thanks, I figured out from jcrews' post that there are two switches. Knowing more about what to look for, I saw the other little bugger way up in there... with a white body, operates on clutch depress-- the starter interlock. CC clutch switch, AKA F36, has a blue body and is mounted below, operates (closes) on clutch pedal release. Please bear with me, I'm still learning here! Thanks for all replies and patience!

At any rate, pushing the clutch made no difference with the measuring blocks, so I'm thinking it's dead. Wiring diagram shows it as a "mechanically operated normally closed" switch. Tried jumping it out, but didn't do anything as far as driving the car- CC still didn't work, and probably caused the "implausible signal" fault code I picked up. I'm guessing that's because it didn't ever open when the clutch was pushed while driving.

Here's a shot of the Ross-Tech screen with the CC switch (only) in the ON position.
http://pics.tdiclub.com/data/uploads/53378/Ross-Tech_Ms_Blk_6-1.JPG

Guess I'll pick up a switch, re-read the "secret twist" instructions and install....

This is a good example of why I tell my students, "You think homework/learning stops when you're an adult?? Think again!"

Clutch switch broken!

http://pics.tdiclub.com/data/uploads/53378/DSC01801.JPG

Actually found the problem (A problem)! The contact arm inside the clutch switch is held in place by two tiny rivets; outboard of the second one, there appeared what looked like a dent, but turned out to be a stress fracture. Slight pressure with finger, and the arm separated. (Note how it's skewed to the side.)

As a result of the stress crack, the contact arm was unable to maintain sufficient "springiness" to remain in contact with the base under normal/at rest (clutch NOT depressed) conditions. A normally closed switch became permanently open....

New clutch switch on order; hopefully that was the only issue!

CC Switch

The saga (and my learning) continues...
I've now verified that the digits on VAG-COM for Measuring Block 6 are identical to the ones wingnut posted, with the addition of a couple of zeroes on the left. All zero-to-1 and 1-to-zero changes I've observed are for the same switches, in the same positions.
I did finally get the clutch switch "1" to change to a zero with a small jumper-- it was just tricky, don't know why, to get a solid connection, which is why it didn't work before. At any rate, zero with the jumper, a change to 1 with jumper pulled. New clutch switch should be in tomorrow.
I do, however, show a 1 in the second from right position on the Switch Monitor section. That 1 has always been there, and doesn't flicker at all. Wingnut found that digit ("CC and Memory OFF") was connected to the stalk switch. In the wiring diagram, sure enough it shows FOUR, not 3, leads from the stalk switch. Somewhere there's still a glitch in that circuit.... On/Off, SET, and RES stalk switches all show ones in the appropriate spots when pushed during testing.
I'll try the contact cleaner route on the stalk switch again, but unfortunately my switch has a larger sub-cover under the pop-off switch cover than wingnut's. Contacts are not visible at all. Has anyone ever had these stalks apart? jcrews-- I did verify that there's a "G" (two of them, actually) in the "Component Number" section of the VAG-COM screen... according to Ross-Tech, a G in that section indicates CC is enabled.

I finally did get a zero to show up in the CC/memory position (second from right on "switch monitoring"). I had worked some contact cleaner in, moved the switch around....

I found I could only get a zero to appear if, after CC switch was clicked into the ON position, I slid the on/off switch back toward the off position, just enough to feel spring tension against it, but not enough to click all the way into the off position. If held that way, a zero would appear and stay, but as soon as pressure on the switch was relaxed, it would revert to "1."

Sounds like a problem in the stalk switch... any other thoughts out there?

4 years and 50K miles, and switches seem to be falling apart.

Success!

This will be my last post on this thread....

I received the new clutch switch today from the dealer, and took the time to show the service manager and service tech why/how the clutch switch had failed.

I had put a good amount of an electrical contact cleaner through the CC stalk switch over the weekend, which may have done the trick or at least helped... when the new clutch switch was installed, the appropriate digit (third from right, "Pedal Monitoring") changed from 1 to zero, changed back to 1 when the clutch was pushed, back to zero when clutch was released, as expected, but...

Went out for a test drive, and the cruise control now works!

Apparently NOT the stalk switch (or was it the contact cleaner??), but we have one happy camper at the moment!

Next, I'll re-assemble the pieces around the steering column and under-dash, and thank the gods once again for not having to remove the steering wheel & replace the turn signal/CC stalk switch-- another bullet dodged!

Many thanks to wingnut, jcrews, LizardRuss, bf1967 (and Ross-Tech) and others who have been very helpful to a noob on this!!

...And to think, if I had had VAG-COM before now, I could most likely have saved a $189 trip to the dealer.

You can fix the brake and clutch switches

To fix them requires a slight level of mechanical abbility, and some small flat head screwdrivers.

simply
lightly pry outward on the small locks on the side of the main body of the switch,
then be careful as a spring will eject rapidly of you open it too quickly.
remove the plunger, then the rest of the innards, carefully depress the stop tabs on the locks, and remove it.
align all parts and reinstall carefully noting position of the locking tabs.
reinstall in vehicle with switch fully depress and turn to wire connection up
gently release brake lever and you should hear it snap in place as it sets the plunger.


THIS IS FOR THE ORRIGINAL EQUIPTMENT SWITCHES ONLY----GREEN ONES

Thanks!

These instructions worked for fixing the clutch switch on my '04 jetta wagon. After replacing the clutch hydraulics last fall (required removing the clutch pedal assembly), everything worked fine except for the cruise control.

Following the .pdf instructions, I removed the clutch switch, unlocked it, pulled out the plunger, and re-installed. Voila! cruise control works like a charm.