this is easy
1: is top hose on radiator too hot to touch , after 10 miles,
yes,then motor is running close to180 to 195f ( the 2 diff, type stats.
next with motor hot , measure ( with an ohm meter setting on dmm)
the shell to center pin resistance. (disconnect wire pin (single it is)
and connect meter to the sender.
it will read about 40 ohms
if it does the sender is good.
test the guage.
connect a 194 trim lamp, used on side markers.
from this wire to ground
guage will to hot.
the lamp shunts the guage safely.
some manuals say to short the wire to ground ,id avoid that,
us a lamp,
there aremany lamps that can work,this limits current if there is a short in the speedo head, and im a cautious tester.
using them lamp.
can only be 4 things.
loss of power to speedohead.
bad wires. (andconnections)
bad guage (rare)
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