A mechanic changed the backup light switch on my 3 speed transmission in my Dodge Caravan 1996, 3.0 engine, the other day and ever since the speedometer does not work intermittently, the Check Engine Light has come on and it points to the VSS. Can changing the backup light switch interfere with the normal operation of VSS, since we never had this problem before? Is the replacement of VSS an easy thing to do? Is it easily accessible? Where exactly should I look for it? Thanks Matt