A/C Switch Input Test

Exc. 1987---88 Accord & 1988 Prelude
1. Connect system checker harness between ECU and wire harness connector.
2. Start engine and place blower switch to ON position.
3. Place A/C switch to ON position.
4. Check that compressor and condenser cooling fan operate.
5. Measure voltage between B8 terminal (blue/red) and A18 terminal (black/red) of system checker harness.
6. Zero to 3 volts should be obtained. If not, repair open circuit between A/C diode coupler and ECU (blue/red wire). Voltage will exceed 9 volts if compressor or condenser cooling fan stops when power is cut-off by the pressure switch or thermostat.