speedometer and brake problems, HELPPP!

[jodiemeglio]

howdy, i have a 91 awd safari and i have some strange problems.
a. my speedometer likes to work whenever it feels like it, which is hardly ever. even when it does work it's jumpy and i doubt its reliability. do these things have a cable or are they electric?

b. my abs light is driving me crazy!!! it came on and i started working on the front brakes. i had a bad caliper on the drivers side and a bad hose on the passengers side. now my brakes are working perfectly but the abs isn't working and the light is still on. i work in a garage and i plugged the abs computer into the thing. it's giving me codes 61 and 62- brake sensor reset. what is that??? we don't have a code guide for the abs machine so i'm lost. i reset the codes with the computer but they came back on. i then tried jumping the abs plug with the ground and i heard the computer reset. they came back on again! what is going on?? i don't know much about abs and it's getting really frustrating with the no speedometer and abs light on. oh yeah when i turn the key the abs light comes on and a second later the brake light comes on. the wheel bearing on the driver's side front is starting to go out but i'm going to let that wait until spring to replace it. would that trigger the abs light to get the codes i'm getting??

one more thing that doesn't really bother me all that much. where is the coolant temperature sensor, the one for the guage? that's not working either.

any help is appreciated!!