Pinpoint Test AA: The Taxi Roof Lamp Is Inoperative Or Always On

Commercial Service Equipment

Pinpoint Test AA: The Taxi Roof Lamp Is Inoperative Or Always On

Refer to Wiring Diagrams Set 140, Customer Access for schematic and connector information. Electrical Diagrams

Normal Operation

Voltage is provided at all times to the taxi roof lamp switch from the Central Junction Box (CJB). When the taxi roof lamp switch is activated, voltage is provided to the taxi roof lamp.

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- Taxi roof lamp switch

- Taxi roof lamp

PINPOINT TEST AA : THE TAXI ROOF LAMP IS INOPERATIVE OR ALWAYS ON

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

AA1 CHECK THE TAXI ROOF LAMP SWITCH VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

- Ignition OFF.

- Disconnect: Taxi Roof Lamp Switch C2213.

- Measure the voltage between the taxi roof lamp switch C2213-2, circuit 30-NC11 (RD), harness side and ground.





Is the voltage greater than 10 volts?

Yes
GO to AA2.

No
VERIFY the CJB (Central Junction Box) fuse 154 (15A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Electrical Diagrams

AA2 BYPASS THE TAXI ROOF LAMP SWITCH

- Connect a fused jumper wire between the taxi roof lamp switch C2213-2, circuit 30-NC11 (RD), harness side and the taxi roof lamp switch C2213-1, circuit 30S-NC11 (RD/WH), harness side.





Does the taxi roof lamp illuminate?

Yes
REMOVE the jumper wire. INSTALL a new taxi lamp switch. TEST the system for normal operation.

No
REMOVE the jumper wire. GO to AA3.

AA3 CHECK THE TAXI ROOF LAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

- Connect: Taxi Roof Lamp Switch C2213.

- Disconnect: Taxi Roof Lamp C994.

- Activate the taxi roof lamp switch.

- Measure the voltage between the taxi roof lamp C994-1, circuit 30S-NC11 (RD/WH), harness side and ground.





Is the voltage greater than 10 volts?

Yes
CHECK and REPAIR the ground circuit or INSTALL a new taxi roof lamp as necessary. TEST the system for normal operation.

No
REPAIR the circuit. TEST the system for normal operation.