Back-up power source circuit

This is the back-up power source circuit for the air conditioning amplifier. Power is supplied even when the ignition switch is turned off and is used for functions such as the diagnostic trouble code memory.

1. 1
   Inspect fuse (ecu-b2)
2. 2
   Remove the ecu-b2 fuse from the engine room no. 2 Relay block.
3. 3
   Measure the resistance of the fuse.

Standard resistance: below 1

2. Check wire harness (air conditioning amplifier - battery)

1. 1
   Disconnect the e37 amplifier connector.
2. 2
   Measure the voltage of the wire harness side connector.

Standard voltage

3. Check wire harness (air conditioning amplifier - body ground)

1. 1
   Disconnect the e37 amplifier connector.
2. 2
   Measure the resistance of the wire harness side connector.

Standard resistance