Corsa Dash Temp gauge Troubleshooting guide
This is for 65-66 dashes. EM Spyder dashes will be the same except for Wire color / placements
System Check with COLD engine:
1 with key "ON" is gauge"
Always over 600 f = good 12vdc to gauge / no ground
Rises to over 600f = shorted lead to Thermister / shorted T-M.
Needle moved but under 200f = gauge funtioning / open circuit to thermister / T-M bad
Thermister / wiring checks
2 wire plug behind dash / Black with light green stripe should read 4,000-6,000 ohms to GROUND
High Temp lead from T-M should read 4-6k ohms
Thermister should read 4-6k ohms
With Dash Harness unplugged:
Black / lt Green wire to dash [ 2nd pin in from row across from open hole] to Black / Purple wire in plug [ 2nd pin over from empty hole]
should read 50 ohms [ gauge good ]
with dash harness pugged in / key ON and T-M disconnected you should see 10 VDC clear
back to T-M.