I have a 1993 chevy G20 van and the speedometer quit working and the trans wont shift out of first after I changed the battery, spark plugs, and air filter. Someone told me to check the speed sensor, so i replaced the speed sensor and it didn't fix the problem. Is there a way to test the speed sensor or the connection. Please let me know as soon as possible. Thank you.

Most of the later VSS are optical, not magnetic. The only reliable way to test is with either a datalogging scanner or a logic probe at the wire harness.

in your 93 you can check it with a dmm and check the ohm rating on all vss, if one is out in left feild, its bad, i beleve 15k to 20k ohms is exceptable