Diagnostic Routine T

2012 Ford Focus L4-2.0LSECTION Diagnostic Routine T



Diagnostic Routine T

Diagnostic Overview

A Puddle Lamp Is Inoperative Or Always On

Refer to Wiring Diagram Set 89 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

REFER to Courtesy Lamps .

DTC Fault Trigger Conditions






Visual Inspection and Diagnostic Pre-checks

- Inspect the bulbs and make sure they are OK.

- Inspect the exterior mirror for damage.

Pinpoint Test

1. CHECK THE OPERATION OF THE INTERIOR COURTESY LAMPS

1. Ignition ON.

2. Ignition OFF.

3. Open and close a door.

4. Observe the interior courtesy lamp operation for 30 seconds.

Do the interior courtesy lamps operate correctly?







2. CHECK THE PUDDLE LAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE

1. Disconnect: DDM (Driver Door Module) C501B (left puddle lamp).

2. Disconnect: Passenger Door Module (PDM) C652B (right puddle lamp).

3. Ignition ON.

Does the puddle lamp continue to illuminate?







3. CHECK THE MIRROR OPERATION

1. Ignition ON.

2. Using the exterior mirror control switch, operate the exterior power mirrors.

Do the exterior power mirrors operate?







4. CHECK FOR VOLTAGE TO THE PUDDLE LAMP

1. Ignition OFF.

2. Disconnect: Inoperative Exterior Mirror.

3. Ignition ON.

4. Open any door.

5. Measure:





Is the voltage greater than 11 volts?







5. CHECK THE PUDDLE LAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO GROUND

1. Ignition OFF.

2. Disconnect: DDM (Driver Door Module) C501B (left puddle lamp).

3. Disconnect: PDM (Passenger Door Module) C652B (right puddle lamp).

4. Measure:





Is the resistance greater than 10,000 ohms?







6. CHECK THE PUDDLE LAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

1. Measure:





Is the resistance less than 3 ohms?







7. CHECK THE EXTERIOR MIRROR GROUND CIRCUIT

1. Measure:





Is the voltage greater than 11 volts?







8. CHECK THE PUDDLE LAMP GROUND CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Disconnect: DDM (Driver Door Module) C501B (left puddle lamp).

3. Disconnect: Passenger Door Module (PDM) C652B (right puddle lamp).

4. Measure:





Is the resistance less than 3 ohms?






RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.