I have a 1997 VW Jetta GLS 2.0 Auto. The cruise control works somedays then doesnt the next day. Its no big deal but I do travel alot and would like to have it functioning properly. What do I need to look for and where and what to check? Any and all help is appreciated.
Lots o stuff. Too much to mention and probably won't help you unless you have a bentley manual and then you can read the troubleshooting tips for yourself.
HTH
Does the speedometer work when the cruise control is acting up? What about the MFA (if your car has one)? When the cruise does not work, does it just fail to turn on, or does it disengage while you are driving with the cruise control turned on?
There is a vacuum pump that operates the cruise control (not sure where it is located in a '97). From the pump there is a hose with a Y adapter in it, one branch goes to the cruise actuator next the the throttle, the other going in to the cabin to the valve on the brake pedal. A vacuum leak anywhere in the hoses, adapters, actuator, switch etc. could cause the cruise control not to work.
The vacuum valve at the brake pedal also has an electrical switch in it. If the valve/switch unit is not adjusted properly, the control unit may think you re stepping on the brakes when you are not, thus disabling the cruise control.
Finally, on my brother's car (a decade older than yours) the "set" switch on the cruise control stalk is somewhat flaky. It takes a firm press to get it to engage.
97JettaGLS wrote:Thank you very much for your replies. =) To answer your questions.. The speedometer is working the whole time. What is the MFA? I am assuming it has to do with a turbo wich my car does not have turbo =( The cruise system fails to work or engage. It doesnt stop working while in use. When it does work I can hear a relay under the dash and I feel the accelerator move away from my foot. I am unsure of where my vaccum pump is but I know the diaphram for the accelorator is just above the pedal. I have adjusted the brake switch but I havent taken it out to test it yet. I dont think there is a vaccum leak at all cause when it does work it works very well. I suspect the set switch but I smack it and nothing happens still.. After the system does work it fails to work again after parking the car or turning it off.
I will bet its the computer. I have seen it go out on two a3's. its the strangest thing, works perfect some days. but others it would never kick on, or just turn off. I picked up a used one from the junk yard for $25 and its worked perfect from that point on. My main car was a 97 too :) the computer is under the dash, its a small silver box, bolted to the alarm box. its a bit of a pain to get to tho. good luck!
Dan From VWsport.com NNTP Gateway
try looking at the brake light switch.......
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