Still Faulty Speedo

[P-O.Selander@ccgate1.exu.ericsson.se (P-O Selander)]

OK, after coming back from Sweden after the Holidays it 
is time to start workingon my faulty speedo again.
What happened was that the cable harness from the 
sending unit at the gear box got ruptured (and probably 
thereby creating some shorts before the fuse (number 12) 
blow (and thereby also cutting power to the temp meter). 
I have since spliced the cables together, but still no 
action.
Does anyone have any instruction/ideas how to test that 
the sending units is OK and sends the "correct" signals? 
Want to do this befere taking my dash out again and 
disassemble the instrument cluster.

TIA  /// P-O Selander
'89 100E
'91 300ZXTT