Power Distribution Relay: Description and Operation

Functions
1. Turn signal flashing
2. Hazard warning flashing
3. Turn signal flashing in hazard warning mode
4. Hazard warning flashing when anti-theft alarm (ATA) is triggered
5. Turn signal flashing with trailer
6. Wiper system
7. Heated rear window

1. Turn signal flashing
The turn signals on the "left" and "right" are controlled by one wire.
Left with resistance of 200 Ohms, right with no resistance (voltage code).
The turn signals are actuated from terminal 15 (fuse 15, fuse box F3 in fuse and relay box F1) by the combination switch (S4) and combination relay (N10, N10/2).

The indicator lamps in the instrument cluster (A1) are actuated by the output from the combination relay (N10, N10/2) and the rear turn signal lamps via the connector for the taillamp harness (X18).

The front turn signal lamps are actuated by the taillamp harness connector (X18) via the headlamp harness connector (X24).

The auxiliary turn signal lamps are connected to the front turn signal lamps.

The flashing frequency is doubled if a bulb is defective.

2. Hazard warning flashing
The hazard warning flasher system is switched on and off by the hazard warning flasher switch.

When the hazard warning flasher system is switched on the electronic circuitry in the combination relay (N10, N10/2) recognizes that it has been switched on.

3. Turn signal flashing in hazard warning mode
When the hazard warning system is switched on and the key in the steering lock is in position 2 the respective turn signal lamp (right or left) is actuated when the combination switch (S4) is operated. The hazard warning system does not operate during this time.

4. Hazard warning flashing when anti-theft alarm is tripped
When the ATA is tripped both flashing light outputs flash at double frequency. The indicator lamp in the hazard warning flasher switch remains switched off.

The hazard warning function and turn signal flashing are retained.

5. Turn signal flashing with trailer
When towing a trailer, the combination relay (N10/2) is actuated by microswitch X58s1. When towing a trailer the electronic circuitry in the combination relay (N10/2) is switched over by a signal to four bulbs (sedan) or three bulbs (coupe) when the turn signals are operated. If a bulb is defective, the flashing frequency is changed.

6. Wiper system
The following functions of the wiper system are actuated in the combination relay (N10, N10/2).
- Intermittent mode
- Touch wipe
- Follow-up wipe
- Continuous wipe (fast and slow)
- Blocking protection

The wiper stages are activated by fuse 15 (terminal 15R), the combination relay (N10, N10/2) and the combination switch (S4). In the intermittent mode and for touch wipe the combination relay (N10, N10/2) is actuated voltage coded by various resistors installed in the combination switch (S4). The third wipe stage is actuated without series resistor.

The wiper system features a blocking protection. The wiper motor cycle is monitored by terminal 31b. If a cycle lasts longer than 12 - 15 seconds, the wiper motor is switched off electronically.

7. Heated rear window
The rear window can be switched on with pushbutton (S14). The electronic circuitry in the combination relay (N10, N10/2) switches off the power output from the time delay relay for the heated rear window when:
- Voltage is not present at terminal 15R.
- The battery voltage is less than 10.6 volts.

In this case the indicator lamp in the button (S14) flashes.

The heated rear window is switched on again automatically when the voltage is 0.6 to 1 volt greater than the switch-off voltage.

If the heated rear window is switched on and off four times within 60 - 64 seconds, the control output is switched off and the indicator lamp in the pushbutton goes out.

The heated rear window switches off automatically after it has been switched on for 15 ± 5 min.

Illumination is accomplished via terminal 58d and an LED in the pushbutton.