1999 Volkswagen Passat electrical problem

I just bought a 99 Passat with the same problem, if you dissconnect the abs module everything goes back to normal. Except the abs warning light stays on, abs module is on the drivers side inner fender. If you pull the block end of the connector out and upwards then you can disable the abs system, mine ended up having a fried abs module, sometimes with VW and Audi you can get away with cleaning out corrosion from the plug and socket and be ok. I would try to clean out first and use a little dielectric grease. You may get lucky.