Pinpoint Test K: One Or More Stoplamps Are Inoperative

Stoplamps

Pinpoint Test K: One Or More Stoplamps Are Inoperative - Milan/MKZ

Refer to Wiring Diagram Set 90 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Turn Signal/Stop/Hazard Lamps for schematic and connector information. Diagrams By Number

Normal Operation

When the brake pedal is applied, the stoplamp switch routes voltage to the high mounted stoplamp and both rear stoplamps. Each stoplamp has an independent ground circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- High mounted stoplamp
- Rear lamp assembly

PINPOINT TEST K: ONE OR MORE STOPLAMPS ARE INOPERATIVE - MILAN/MKZ

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

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K1 DETERMINE THE INOPERATIVE STOPLAMP

- Ignition OFF.
- Apply the brake pedal and observe the stoplamps.
- Are all the stoplamps inoperative?

Yes
GO to Pinpoint Test I. Pinpoint Test I: All The Stoplamps Are Inoperative

No
For the high mounted stoplamp, GO to K2.

For a LH or RH rear stoplamp, GO to K4.

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K2 CHECK FOR VOLTAGE TO THE HIGH MOUNTED STOPLAMP

- Disconnect: High Mounted Stoplamp.
- For a spoiler high mounted stoplamp with a rear view camera, while applying the brake pedal, measure the voltage between the high mounted stoplamp C4199-3, circuit CCB08 (VT/WH), harness side and ground.

- For a spoiler high mounted stoplamp without a rear view camera, while applying the brake pedal, measure the voltage between the high mounted stoplamp C4111-1, circuit CCB08 (VT/WH), harness side and ground.

- For a parcel shelf high mounted stoplamp, while applying the brake pedal, measure the voltage between the high mounted stoplamp C475-1, circuit CCB08 (VT/WH), harness side and ground.

- Is the voltage greater than 10 volts?

Yes
GO to K3.

No
REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.

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K3 CHECK FOR VOLTAGE TO THE HIGH MOUNTED STOPLAMP USING THE CONNECTOR GROUND

- For a spoiler high mounted stoplamp with a rear view camera, while applying the brake pedal, measure the voltage between the high mounted stoplamp C4199-3, circuit CCB08 (VT/WH), harness side and the high mounted stoplamp C4199-1, circuit GD171 (BK/GY), harness side.

- For a parcel shelf high mounted stoplamp, while applying the brake pedal, measure the voltage between the high mounted stoplamp C475-1, circuit CCB08 (VT/WH), harness side and the high mounted stoplamp C475-2, circuit GD171 (BK/GY), harness side.

- Is the voltage greater than 10 volts?

Yes
INSTALL a new high mounted stoplamp. TEST the system for normal operation.

No
REPAIR circuit GD171 (BK/GY) for an open. TEST the system for normal operation.

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K4 CHECK FOR VOLTAGE TO THE LH STOPLAMP

- Disconnect: Inoperative Rear Stoplamp.
- While applying the brake pedal, measure the voltage between the LH rear lamp C419-1, circuit CCB08 (VT/WH), harness side and ground; or between the RH rear lamp C418-1, circuit CCB08 (VT/WH), harness side and ground.

- Is the voltage greater than 10 volts?

Yes
GO to K5.

No
REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.

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K5 CHECK FOR VOLTAGE TO THE INOPERATIVE STOPLAMP USING THE CONNECTOR GROUND

- While applying the brake pedal, measure the voltage between the LH rear lamp C419-1, circuit CCB08 (VT/WH), harness side and the LH rear lamp C419-3, circuit GD171 (BK/GY), harness side; or between the RH rear lamp C418-1, circuit CCB08 (VT/WH), harness side and the RH rear lamp C418-3, circuit GD171 (BK/GY), harness side.

- Is the voltage greater than 10 volts?

Yes
INSTALL a new rear lamp assembly. REFER to Rear Lamp Assembly [1][2]Rear Lamp Assembly. TEST the system for normal operation.

No
REPAIR circuit GD171 (BK/GY) for an open. TEST the system for normal operation.

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