The speedo & odom & trip do not work the head i tryed in my 89 and it works what i found so far a unit screws into the trans has a small cable inside trans with two elec wires that go over top of trans are there fuses or relays or other components that i need to look and what tests can i do to check can i put a drill on the rod that goes into the trans and spin it and see a result any help is welcome thank you

 

Those speedo transducers are a common culprit.

I think they generate some sort of wave form, so you'd need scope to check it properly. Perhaps a test light or meter could be used to determine if it is flat-out dead or not. No output at all suggesting it is dead, while some sort of output only proves it isn't flat-out dead. Hopefully others will chime in on that.

Sometimes the wires get burned on the exhaust pipe, so there's something to look for.

In the end I'm pretty sure you'll be replacing the transducer

Cheers
RTLL