Operation CHARM: Car repair manuals for everyone.
Home >> Honda >> 1986 >> Prelude L4-1955cc 2000 >> Repair and Diagnosis >> Heating and Air Conditioning >> Testing and Inspection >> Component Tests and General Diagnostics >> Component Testing >> A/C Switch Input Test
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

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.


pro multis · About Operation CHARM