Cruise control on a 2001 VW Jetta?

Question

Recently I started having problems with the cruise control (cc) on my 2001 VW Jetta. It takes 30 seconds to several minutes of holding the cc switch to the left to get the cc to engage. In the past, it would engage within seconds. Once the cc is engaged it sometimes works fine. Other times the cc will engage and start accelerating very quickly, only to disengage on it's own after about 15 seconds.

Last night I was on the interstate and I tried to set the cc to 60 mph. The cc engaged, accelerated to about 66 mph and then disengaged by itself. I could not get it to work again after that. This morning I took the car out to test it. It took over a minute of holding the cc switch to the left before it engaged but then it worked normally.

Does this sounds like a known problem, something I could fix myself with basic repair skills?

Answer 1

First have your brake light switch checked.  Have someone drive behind you while your trying to use the cruise control and have them tell you if your brake lights turned on while you where drving.

If the brake switch is bad, when it freaks out, it will tell the computer your stepping on the brake and kick you out of cruise control.

Second most common would be the turn signal assembly with the cruise control switch on it.  The wires wear out as you move the turn signal stock up and down to turn on your blinkers.

Also if any Soda, Water, Windex, Armorall gets on the switch it shorts out the inside.

Those 2 would be the most comnmon.  Try these out and let us know...

Ok, so to be ABSOLUTLEY sure whats going on.  The car needs to be hooked to a FACTORY scanner.  Then the car needs to be put up in the air so the tires can spin, and the cruise control can be engauged.  Watching Value Blocks in the scanner will show which sensor is telling the cruise to turn off.  

It turns out that the brake light switch CAN turn the cruise control off even if the brake lights still work.  So that would be the CHEAPEST thing to check first.  They fail ALL the time.  So putting in a new one to try wouldn't hurt.  There was actually a recall.  Did you have that done?  The newest brake switch is green.  They were black, purple, and now green.  Still failing just as frequently, often within a week of installation.  One of V.W.'s downfalls for sure.

Then the turnsignal switch, which is very expensive to fix.  It is very possible that JUST the cruise portion of the switch has begun to fail.  MOST of the time it's the turn signals that fail because it get used hundreds of times more than the cruise switch.  But in the event that something got into the switch in the form of liquid, it could have been shorted out.

After asking some other VW Techs at the dealer, they say there is a switch on the clutch pedal that fails very rarely.  But when it starts to fail, it kicks cruise control off intermittently too.