Quote:
Originally Posted by gitter
Ok here's what I have so far:
1. with key ON, test for power at harness-side connector brown/black wire
12.6V
2. with key ON, test for power at gauge-side connector brown wire
12.3V
3. measure resistance between chassis-ground and harness-side connector black/yellow wire
.2
4. measure resistance between chassis-ground and gauge-side connector black/yellow wire
.3
|
This is good, means we're getting power to the gauges across the connector. They also have good grounds to chassis
Quote:
Originally Posted by gitter
unplug ECU connector
5. measure resistance between ECU-connector black wire and harness-side connector black wire
.3
6. measure resistance between ECU-connector black wire and guage-side connector black wire
.3
7. measure resistance between ECU-connector black wire and chassis-ground
3.7
|
Good that black signal wire is intact to tach. NOT GOOD that it's shorted to ground somewhere between ECU-connector and coil/tach.
I guess you'll have to unwrap the loom starting at the ECU-connector and work your way forwards inspecting black coil wire along the way. At some point, it's frayed with a bare-spot and connecting to ground. Or where it splits off to tach may be shorted as well. Hmmm, maybe a short inside the tach?
Try this final test before unwrapping:
8. disconnect black signal-wire from coil
9. unplug gauge-connector from harness connectors
10. measure resistance of black-wire between ECU-connector and coil spade-connector
11. measure resistance of either end of black signal-wire to chassis-ground
If it has infinite-resistance (open), then we know there's short between tach and gauge-connector.
Otherwise, there's still short along way from ECU to coil, and we'll need to open up loom and inspect entire length of that black wire.
You can use the 'noid-light to test signal as well. Start at ECU-connector's green coil-wire as control to confirm light works. Then switch to black-wire terminal and verify ECU's sending out correct grounding signal (use any +12v for other terminal of 'noid-light). Then work your way up black wire and see where signal stops.