speedometor question

[long tall eta]

guys, a friend on mine has an 86es automatic. his speedo quit. if not the sensor, what else would cause the failure? is there a test to determine if it's the sensor? if it is the sensor, do you have to drain the diff to change it?

[Court M3]

Don't have to drain the diff, it's located on the side of the diff. Check to make sure the wiring is secured.

Maybe swap with a known good one to check sensor? Also check and the gears, might be stripped?

[long tall eta]

Don't have to drain the diff, it's located on the side of the diff. Check to make sure the wiring is secured.

Maybe swap with a known good one to check sensor? Also check and the gears, might be stripped?

thank you.

[Gregs///M]

Also check fuse 10, 12, and 21.