| Diagnosis and Testing Refer to Wiring Diagrams Section 501-16, for schematic and connector information. Special Tool(s) | | Terminal Probe Kit 29-011A | Diagnosis and Testing NOTE:If the generic electronic module (GEM) is changed, the new one must be configured. For this purpose, the vehicle-specific data is read out of the module to be replaced using WDS and is transferred to the new module. REFER to: Kommunikations-Netzwerk - gebaut ab 02/2005 (418-00, Diagnosis and Testing). NOTE:Before reading out the vehicle-specific data, remake all the electrical connections which were separated in the vehicle, so that communication between the module and WDS is ensured. - Verify the customer concern.
- Visually check for any obvious mechanical or electrical damage.
Visual Inspection Chart | Mechanical | Electrical | - Windscreen wiper blade(s)
- Wiper pivot arm shaft
- Washer reservoir
- Hose(s)
- Nozzles
| - Fuse(s)
- Connectors
- Wiring harness
- Washer pump motor, front and rear
- Front wiper motor
| - Resolve any obvious causes or concerns found during the visual inspection before carrying out any further tests.
- If the concern is not visually evident, refer to the Symptom Chart.
Symptom Chart Symptom Chart | Symptom | Possible Sources | Action | | The windscreen wiper is inoperative | * Fuse * Circuit(s) * Steering column multifunction switch. * Front wiper motor * Central junction box (CJB) | * | | Brief wipe is inoperative (slow wipe OK) | * Steering column multifunction switch. | * INSTALL a new steering column multifunction switch. CHECK the operation of the system. | | The windscreen wiper runs continuously | * Circuit(s) * Steering column multifunction switch. * Front wiper motor | * | | Fast or slow wipe speed inoperative | * Circuit(s) * Steering column multifunction switch. * Front wiper motor | * | | Intermittent wipe mode inoperative (fast/slow wipe OK) | * Circuit(s) * Steering column multifunction switch. * GEM (Generic electronic module) | * | | The wipers do not return to the park position after switching them off | * Circuit(s) * Steering column multifunction switch. * Front wiper motor * GEM (Generic electronic module) | * | | The wash/wipe function is inoperative (wipe and intermittent function OK) | * Circuit(s) * Washer pump motor, front and rear * Steering column multifunction switch. * GEM (Generic electronic module) | * | Pinpoint Testing NOTE:Use a digital multimeter for all electrical measurements. | PINPOINT TEST A : THE WINDSCREEN WIPER IS INOPERATIVE | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | A1: DETERMINE THE FAULT CONDITION | | | 1 Ignition switch in position II. | | | 2 SWITCH ON slow wipe speed. | | | 3 SWITCH ON fast wipe speed. | | | 4 CHECK windshield wiper. | | | Are both speeds inoperative? Yes No Only one speed inoperative: GO to Pinpoint Test C. | | A2: CHECK FUSE F16 (20 A) (CJB). | | | 1 Ignition switch in position 0. | | | 2 Disconnect Fuse F16 (20 A) (CJB). | | | 3 CHECK Fuse F16 (20 A) (CJB). | | | Is the fuse OK.? Yes No RENEW fuse F16 (20 A) and check the operation of the system. If the fuse blows again, LOCATE and RECTIFY the short to ground using the Wiring Diagrams. CHECK the operation of the system. | | A3: CHECK THE VOLTAGE SUPPLY TO FUSE F16 (20 A) (CJB) FOR OPEN CIRCUIT | | | 1 Ignition switch in position 0. | | | 2 Connect Fuse F16 (20 A) (CJB). | | | 3 Ignition switch in position II. | | | 4 Measure the voltage between fuse F16 (20 A) (CJB) and ground. | | | Is battery voltage measured? Yes No CHECK and if necessary RENEW the CJB. CHECK the operation of the system. | | A4: CHECK THE VOLTAGE AT THE STEERING COLUMN MULTIFUNCTION SWITCH | | | 1 Ignition switch in position 0. | | | 2 Disconnect Steering column multifunction switch from connector C102. | | | 3 Ignition switch in position II. | | | 4 Measure the voltage between the steering column multifunction switch, connector C102, pin 7, circuit 14-KA19 (VT/OG), wiring harness side and ground. | | | Is battery voltage measured? Yes No LOCATE and RECTIFY the break in the circuit between fuse F16 (CJB) and the steering column multifunction switch using the Wiring Diagrams. CHECK the operation of the system. | | A5: CHECK THE VOLTAGE AT THE FRONT WIPER MOTOR | | | 1 Ignition switch in position 0. | | | 2 Connect Steering column multifunction switch to connector C102. | | | 3 Disconnect Front wiper motor from connector C96. | | | 4 Ignition switch in position II. | | | 5 SWITCH ON slow wipe speed. | | | 6 Measure the voltage between the front wiper motor, connector C96, pin 5, circuit 14S-KA10 (VT/BK), wiring harness side and ground. | | | Is battery voltage measured? Yes No INSTALL a new steering column multifunction switch. CHECK the operation of the system. | | A6: CHECK THE GROUND CONNECTION OF THE FRONT WIPER MOTOR FOR OPEN CIRCUIT | | | 1 Ignition switch in position 0. | | | 2 Measure the resistance between the front wiper motor, connector C96, pin 1, circuit 31-KA8 (BK), wiring harness side and ground. | | | Is less than 2 Ohm measured? Yes RENEW the front wiper motor. CHECK the operation of the system. No LOCATE and RECTIFY the break in the circuit between the front wiper motor and soldered connection S15 using the Wiring Diagrams. CHECK the operation of the system. | | PINPOINT TEST B : THE WINDSCREEN WIPER RUNS CONTINUOUSLY | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | B1: DETERMINE THE FAULT CONDITION | | | 1 Ignition switch in position 0. | | | 2 Disconnect Steering column multifunction switch from connector C102. | | | 3 Ignition switch in position II. | | | Is the front wiper motor on continually? Yes - The front wiper motor is running continually at the slow wipe speed: GO to B2. - The front wiper motor is running continually at the fast wipe speed: GO to B3. No - RENEW the steering column multifunction switch. CHECK the operation of the system. - The front wiper motor runs continuously at slow wipe speed. GO to B6. - The front wiper motor is running continually in intermittent wipe mode: GO to B4. | | B2: CHECK CIRCUIT 14S-KA10 (VT/BK) FOR SHORT TO BATTERY VOLTAGE | | | 1 Ignition switch in position 0. | | | 2 Disconnect Front wiper motor from connector C96. | | | 3 Ignition switch in position II. | | | 4 Measure the voltage between the steering column multifunction switch, connector C102, pin 3, circuit 14S-KA10 (VT/BK), wiring harness side and ground. | | | Is battery voltage measured? Yes LOCATE and RECTIFY the short to battery voltage in the circuit between the steering column multifunction switch and the front wiper motor using the Wiring Diagrams. CHECK the operation of the system. No RENEW the front wiper motor. CHECK the operation of the system. | | B3: CHECK CIRCUIT 14S-KA11 (VT/OG) FOR SHORT TO BATTERY VOLTAGE | | | 1 Ignition switch in position 0. | | | 2 Disconnect Front wiper motor from connector C96. | | | 3 Ignition switch in position II. | | | 4 Measure the voltage between the steering column multifunction switch, connector C102, pin 5, circuit 14S-KA11 (VT/OG), wiring harness side and ground. | | | Is battery voltage measured? Yes LOCATE and RECTIFY the short to battery voltage in the circuit between the steering column multifunction switch and the front wiper motor using the Wiring Diagrams. CHECK the operation of the system. No RENEW the front wiper motor. CHECK the operation of the system. | | B4: CHECK THE STEERING COLUMN MULTIFUNCTION SWITCH | NOTE:The minimum measurement duration is 20 seconds. | | | 1 Ignition switch in position 0. | | | 2 Disconnect Steering column multifunction switch from connector C102. | | | 3 Ignition switch in position II. | | | 4 Measure the voltage between the steering column multifunction switch, connector C102, pin 2, circuit 14-KA15A (VT/OG), wiring harness side and ground. | | | Is battery voltage measured approximately every 10 seconds? Yes No INSTALL a new steering column multifunction switch. CHECK the operation of the system. | | B5: CHECK CIRCUIT 14S-KA14 (VT/BK) FOR SHORT TO BATTERY VOLTAGE | | | 1 Measure the voltage between the steering column multifunction switch, connector C102, pin 10, circuit 14S-KA14 (VT/BK), wiring harness side and ground. | | | Is battery voltage measured? Yes LOCATE and RECTIFY the short to battery voltage in the circuit between the steering column multifunction switch and the GEM using the Wiring Diagrams. CHECK the operation of the system. No REFER to: Zentralelektrikmodul (GEM) (419-10, Diagnosis and Testing). | | B6: NARROW DOWN THE CAUSE OF THE SHORT TO BATTERY VOLTAGE | | | 1 Measure the voltage between the steering column multifunction switch, connector C102, pin 2, circuit 14-AK15A (VT/OG), wiring harness side and ground. | | | Is battery voltage measured? Yes No INSTALL a new steering column multifunction switch. CHECK the operation of the system. | | B7: ELIMINATE THE GEM (GENERIC ELECTRONIC MODULE) AS THE CAUSE FOR THE SHORT TO BATTERY VOLTAGE. | | | 1 Ignition switch in position 0. | | | 2 Disconnect Fuse F1 (20 A) (CJB). | | | 3 Disconnect Fuse F2 (10 A) (CJB). | | | 4 Disconnect Fuse F16 (20 A) (CJB). | | | 5 Disconnect Fuse F17 (15 A) (CJB). | | | 6 Disconnect Fuse F23 (20 A) (CJB). | | | 7 Disconnect Fuse F33 (15 A) (CJB). | | | 8 Ignition switch in position II. | | | 9 Measure the voltage between the steering column multifunction switch, connector C102, pin 2, circuit 14-AK15A (VT/OG), wiring harness side and ground. | | | Is battery voltage measured? Yes LOCATE and RECTIFY the short to battery voltage in the circuits connected to the steering column multifunction switch, connector C102, pin 9 using the Wiring Diagrams. CHECK the operation of the system. No REFER to: Zentralelektrikmodul (GEM) (419-10, Diagnosis and Testing). | | PINPOINT TEST C : FAST OR SLOW WIPE SPEED INOPERATIVE | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | C1: DETERMINE THE FAULT CONDITION | | | 1 Ignition switch in position II. | | | 2 SWITCH ON slow wipe speed. | | | 3 SWITCH ON fast wipe speed. | | | 4 CHECK the windscreen wiper. | | | Do the windscreen wipers operate at fast speed? Yes No | | C2: CHECK VOLTAGE SUPPLY TO FRONT WIPER MOTOR (PIN 5) | | | 1 Ignition switch in position 0. | | | 2 Disconnect Front wiper motor from connector C96. | | | 3 Ignition switch in position II. | | | 4 SWITCH ON slow wipe speed. | | | 5 Measure the voltage between the front wiper motor, connector C96, pin 5, circuit 14S-KA10 (VT/BK), wiring harness side and ground. | | | Is battery voltage measured? Yes RENEW the front wiper motor. CHECK the operation of the system. No | | C3: CHECK THE STEERING COLUMN MULTIFUNCTION SWITCH | | | 1 Ignition switch in position 0. | | | 2 Connect Front wiper motor to connector C96. | | | 3 Disconnect Steering column multifunction switch from connector C102. | | | 4 Using a fused bridging cable (20 A) at the steering column multifunction switch, connect between connector C102, pin 7, circuit 14-KA19 (VT/OG) and pin 3, circuit 14S-KA10 (VT/BK), wiring harness side. | | | 5 Ignition switch in position II. | | | Do the windscreen wipers operate at slow speed? Yes INSTALL a new steering column multifunction switch. CHECK the operation of the system. No LOCATE and RECTIFY the break in the circuit between the steering column multifunction switch and the front wiper motor using the Wiring Diagrams. CHECK the operation of the system. | | C4: CHECK THE VOLTAGE SUPPLY TO THE FRONT WIPER MOTOR (PIN 4) | | | 1 Ignition switch in position 0. | | | 2 Disconnect Front wiper motor from connector C96. | | | 3 Ignition switch in position II. | | | 4 SWITCH ON fast wipe speed. | | | 5 Measure the voltage between the front wiper motor, connector C96, pin 4, circuit 14S-KA11 (VT/OG), wiring harness side and ground. | | | Is battery voltage measured? Yes RENEW the front wiper motor. CHECK the operation of the system. No | | C5: CHECK THE STEERING COLUMN MULTIFUNCTION SWITCH | | | 1 Ignition switch in position 0. | | | 2 Connect Front wiper motor to connector C96. | | | 3 Disconnect Steering column multifunction switch from connector C102. | | | 4 Using a fused bridging cable (20 A) at the steering column multifunction switch, connect between connector C102, pin 7, circuit 14-KA19 (VT/OG) and pin 5, circuit 14S-KA11 (VT/OG), wiring harness side. | | | 5 Ignition switch in position II. | | | Do the windscreen wipers operate at fast speed? Yes INSTALL a new steering column multifunction switch. CHECK the operation of the system. No LOCATE and RECTIFY the break in the circuit between the steering column multifunction switch and the front wiper motor using the Wiring Diagrams. CHECK the operation of the system. | | PINPOINT TEST D : INTERMITTENT WIPE MODE INOPERATIVE (FAST/SLOW WIPE OK) | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | D1: DETERMINE THE FAULT CONDITION | | | 1 Ignition switch in position II. | | | 2 Actuate brief wipe. | | | 3 CHECK the windscreen wiper. | | | Does the windscreen wiper return to the park position? Yes No | | D2: CHECK THE STEERING COLUMN MULTIFUNCTION SWITCH | | | 1 Ignition switch in position 0. | | | 2 Disconnect Steering column multifunction switch from connector C102. | | | 3 Connect two fused bridging cables (20 A) to the steering column multifunction switch, connector C102 between: - pin 7, circuit 14-KA19 (VT/OG) and pin 10, circuit 14S-KA14 (VT/BK), wiring harness side.
- pin 3, circuit 14S-KA10 (VT/BK) and pin 9, circuit 14-KA15A (VT/OG)/14S-KA15 (VT/OG), wiring harness side.
| | | 4 Ignition switch in position II. | | | Do the wipers operate in intermittent mode? Yes INSTALL a new steering column multifunction switch. CHECK the operation of the system. No | | D3: CHECK CIRCUITS 14S-KA14 (VT/BK) AND 14S-KA15 (VT/OG) BETWEEN THE STEERING COLUMN MULTIFUNCTION SWITCH AND THE GEM (GENERIC ELECTRONIC MODULE) FOR OPEN CIRCUIT | | | 1 Ignition switch in position 0. | | | 2 Disconnect GEM from connector C174. | | | 3 Measure the resistance between the steering column multifunction switch, connector C102, pin 9, circuit 14S-KA15 (VT/OG), wiring harness side and the GEM, connector C174, pin 1, circuit 14S-KA15 (VT/OG), wiring harness side. | | | 4 Measure the resistance between the steering column multifunction switch, connector C102, pin 10, circuit 14S-KA14 (VT/BK), wiring harness side and the GEM, connector C174, pin 19, circuit 14S-KA14 (VT/BK), wiring harness side. | | | Do both measurements display a reading below 2 Ohm? Yes REFER to: Zentralelektrikmodul (GEM) (419-10, Diagnosis and Testing). No LOCATE and REPAIR the break in the relevant circuit between the steering column multifunction switch and the GEM using the Wiring Diagrams. CHECK the operation of the system. | | PINPOINT TEST E : THE WIPERS DO NOT RETURN TO THE PARK POSITION AFTER SWITCHING THEM OFF | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | E1: DETERMINE THE FAULT CONDITION | | | 1 Ignition switch in position II. | | | 2 SWITCH ON intermittent wipe mode. | | | 3 CHECK the windscreen wiper. | | | Do the wipers operate with intermittent mode? Yes Only park function inoperative: GO to E2. No Park function and intermittent mode inoperative: GO to E3. | | E2: CHECK THE STEERING COLUMN MULTIFUNCTION SWITCH | | | 1 Ignition switch in position 0. | | | 2 Disconnect Steering column multifunction switch from connector C102. | | | 3 Steering column multifunction switch to "OFF" setting. | | | 4 Measure the resistance at the steering column multifunction switch, connector C102 between pin 2, component side and pin 3, component side. | | | Is less than 2 Ohm measured? Yes LOCATE and RECTIFY the break in circuit 14-KA15A (VT/OG) at the steering column multifunction switch, connector C102, between pin 2 and pin 9, using the Wiring Diagrams. CHECK the operation of the system. No INSTALL a new steering column multifunction switch. CHECK the operation of the system. | | E3: CHECK THE FRONT WIPER MOTOR | NOTE:After actuating brief wipe, the windscreen wiper must be outside the park position. | | | 1 Actuate brief wipe. | | | 2 Ignition switch in position 0. | | | 3 Disconnect Front wiper motor from connector C96. | | | 4 Measure the resistance at the front wiper motor, connector C96 between pin 2, component side and pin 3, component side. | | | Is less than 2 Ohm measured? Yes No RENEW the front wiper motor. CHECK the operation of the system. | | E4: CHECK THE VOLTAGE SUPPLY TO THE FRONT WIPER MOTOR FOR OPEN CIRCUIT | | | 1 Ignition switch in position II. | | | 2 Measure the voltage between the front wiper motor, connector C96, pin 3, circuit 14-KA8 (VT/BU), wiring harness side and ground. | | | Is battery voltage measured? Yes No LOCATE and RECTIFY the break in the circuit between soldered connection S19 and the front wiper motor using the Wiring Diagrams. CHECK the operation of the system. | | E5: CHECK CIRCUIT 32-KA19 (WH/BK) BETWEEN THE GEM (GENERIC ELECTRONIC MODULE) AND THE FRONT WIPER MOTOR FOR BREAKS | | | 1 Ignition switch in position 0. | | | 2 Disconnect GEM from connector C174. | | | 3 Measure the resistance between the GEM, connector C174, pin 3, circuit 32-KA19 (WH/BK), wiring harness side and the front wiper motor, connector C96, pin 2, circuit 32-KA19 (WH/BK), wiring harness side. | | | Is less than 2 Ohm measured? Yes No LOCATE and RECTIFY the break in the circuit between the GEM and the front wiper motor using the Wiring Diagrams. CHECK the operation of the system. | | E6: CHECK THE VOLTAGE SUPPLY TO THE GEM (GENERIC ELECTRONIC MODULE) | | | 1 Ignition switch in position II. | | | 2 Measure the voltage between the GEM, connector C173, pin 3, circuit 14-KA13 (VT/YE), wiring harness side and ground. | | | Is battery voltage measured? Yes REFER to: Zentralelektrikmodul (GEM) (419-10, Diagnosis and Testing). No LOCATE and RECTIFY the break in the circuit between the soldered connection S19 and the GEM using the Wiring Diagrams. CHECK the operation of the system. | | PINPOINT TEST F : THE WASH/WIPE FUNCTION IS INOPERATIVE (WIPE AND INTERMITTENT FUNCTION OK) | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | F1: DETERMINE THE FAULT CONDITION | | | 1 Ignition switch in position II. | | | 2 SWITCH ON the front washer function. | | | 3 CHECK the operation of the wash/wipe function. | | | Is the wash/wipe function inoperative? Yes No - Only wash function inoperative: GO to F3. - Only wipe function inoperative: GO to F7. | | F2: CHECK THE GROUND CONNECTION OF THE STEERING COLUMN MULTIFUNCTION SWITCH FOR OPEN CIRCUIT | | | 1 Ignition switch in position 0. | | | 2 Disconnect Steering column multifunction switch from connector C102a. | | | 3 Measure the resistance between the steering column multifunction switch, connector C102a, pin 8, circuit 31-LE29 (BK), wiring harness side and ground. | | | Is less than 2 Ohm measured? Yes INSTALL a new steering column multifunction switch. CHECK the operation of the system. No LOCATE and RECTIFY the break in the circuit between the steering column multifunction switch and soldered connection S15 using the Wiring Diagrams. CHECK the operation of the system. | | F3: CHECK THE VOLTAGE SUPPLY TO THE FRONT AND REAR WASHER PUMP MOTOR (PIN 1), FOR OPEN CIRCUIT | NOTE:Steering column multifunction switch to OFF setting. | | | 1 Ignition switch in position 0. | | | 2 Disconnect Front and rear washer pump motor from connector C94. | | | 3 Ignition switch in position II. | | | 4 Measure the voltage between the front and rear washer pump motor, connector C94, pin 1, circuit 32-KA34 (WH/BK), wiring harness side and ground. | | | Is battery voltage measured? Yes No | | F4: CHECK CIRCUIT 32-KA34 (WH/BK) FOR OPEN CIRCUIT | | | 1 Ignition switch in position 0. | | | 2 Disconnect Steering column multifunction switch from connector C102. | | | 3 Measure the resistance between the steering column multifunction switch, connector C102, pin 4, circuit 32-KA34 (WH/BK)/32-KA9 (WH/BU), wiring harness side and the front and rear washer pump motor, connector C94, pin 1, circuit 32-KA34 (WH/BK), wiring harness side. | | | Is the resistance less than 2 Ohm? Yes INSTALL a new steering column multifunction switch. CHECK the operation of the system. No LOCATE and RECTIFY the break in the circuit between the steering column multifunction switch and the front and rear washer pump motor using the Wiring Diagrams. CHECK the operation of the system. | | F5: CHECK THE VOLTAGE SUPPLY TO THE FRONT AND REAR WASHER PUMP MOTOR (PIN 2), FOR OPEN CIRCUIT | | | 1 Measure the voltage between the front and rear washer pump motor, connector C94, pin 2, circuit 33-KA34 (YE/BK), wiring harness side and ground. | | | Is battery voltage measured? Yes INSTALL A NEW front and rear washer pump motor CHECK the operation of the system. No | | F6: CHECK CIRCUIT 33-KA34 (YE/BK) FOR OPEN CIRCUIT | | | 1 Ignition switch in position 0. | | | 2 Disconnect Steering column multifunction switch from connector C102. | | | 3 Measure the resistance between the steering column multifunction switch, connector C102, pin 1, circuit 33-KA34 (YE/BK)/33-KA36 (YE/RD), wiring harness side and the front and rear washer pump motor, connector C94, pin 2, circuit 33-KA34 (YE/BK), wiring harness side. | | | Is the resistance less than 2 Ohm? Yes INSTALL a new steering column multifunction switch. CHECK the operation of the system. No LOCATE and RECTIFY the break in the circuit between the steering column multifunction switch and the front and rear washer pump motor using the Wiring Diagrams. CHECK the operation of the system. | | F7: CHECK THE CONTROL CIRCUITS BETWEEN THE STEERING COLUMN MULTIFUNCTION SWITCH AND THE GEM (GENERIC ELECTRONIC MODULE) FOR BREAKS | | | 1 Ignition switch in position 0. | | | 2 Disconnect GEM from connector C172. | | | 3 Ignition switch in position II. | | | 4 Measure the voltage between the GEM, connector C172, pin 3, circuit 32-KA9 (WH/BU), wiring harness side and ground. | | | Is battery voltage measured? Yes REFER to: Zentralelektrikmodul (GEM) (419-10, Diagnosis and Testing). No LOCATE and REPAIR the open circuit between the steering column multifunction switch and the GEM using the Wiring Diagrams. CHECK the operation of the system. | |
