Volkswagen Repair: 98 gti abs and brake light on, wheel speed, 1 5mm

Question
My 98 gti has both the abs and brake lights on.  I checked the brake fluid and its fine.  what could be causing the lights to come on?

Answer
Hi Evan;
There are a couple of things I can think of right off hand.  The first is the easiest to check, but not necessarily the easiest to do.  On the driver's side wheel, brake assembly, look for a brake pad wear indicator.  There should be a 2 wire connector that goes to an insert in the brake pad itself.  Not all 1998's had them, but some did.  While you are there, check and see how the hall effect sensor looks.  There is a magnet about 1.5mm away from the speed sensor wheel.  Together these 2 components make up the wheel speed sensor, you need to look at them all, and see if any of them are disconnected, or broken.  There is one other component it could be, and that is the ABS control module.  I don't know if it is exactly the same as the Passat(starting in 1998), but there should be a control module with a fairly large electrical connector going to it.  On the other side of the module is a metal "box" with 4 screws in it...one on each corner...jiggle the connector, and the box, and see if anything in the instrument cluster changes.  The component you are looking for is below the master cylinder for the brakes.  Finally, it could be simpler than all of these, have you had new tires installed recently?  If so, and if they are larger, or smaller in overall circumference, or diameter by more than 2%, the lights in the dash will come on.  Good luck, Evan.