Contact «15R» indicates the contacts that should function in the key position «I» And «II», as well as when the starter is turned on. The braid is usually black with additional stripes.
Contact «30» is constantly under voltage from the battery or, when the engine is running, from the generator. Therefore, if the tool is handled carelessly, short circuits or sparks are possible on it if the negative terminal is not removed from the battery. The connected wires are current-carrying and, as a rule, have a red braid, if necessary with the addition of additional stripes of a different color.
Contact «30a» is constantly energized from the positive pole of the battery through the fuse. Usually, memory blocks for controller fault codes are connected through it.
Contact «31» – «weight», through which consumers are connected to «mass» car to complete the circuit. The wires are brown.
Contact «49» responsible for the system of direction indicators and alarms. The color of the wires is black-green with additional stripes of a different color.
Contact «50» - through it, during start-up, voltage is supplied to the starter. The main wire color is purple.
Contact «53» responsible for the windshield wiper.
Contact «56» is responsible for supplying voltage to the low beam headlights through the yellow wires and to the high beam headlights through the white wires.
Contact «58» is responsible for the parking and position light, as well as license plate lighting. The main color of the wire sheath is gray, each with an additional stripe of a different color.
Contact «61» responsible for the charging indicator lamp («D+»), wire color is blue.
Contact «87» energized normally, like a contact «15», but through a relay, such as surge protection.
Wire connectors
For a long time, according to ADAC statistics, disconnected connectors were one of the most common causes of malfunctions, and in almost all cars. Against this misfortune, which happens especially often after six years of operation, Mercedes has applied several innovations. First of all, the car uses a lot of expensive silver-plated round plugs. Plug-in combs have additional mechanical protection. It is clear that in order to disconnect connections, this protection must be surmountable. Therefore, this is either a bracket or two side latches that must be compressed to disconnect the contact connector. Some plugs have twist or spring locks. If possible, connectors and devices are well protected from moisture.
Battery power wires
Pic. 9.37. When the upholstery is removed, the power cable coming from the battery is visible (1) driver's legroom; shaft (2) steering wheel with extension for adjustable steering column; red plug connection (3) to the airbag
To supply current from the battery installed at the rear, a red power wire with a large cross section is connected to the positive terminal of the battery in the engine compartment (pic. 9.37). Further, it passes into the thick (50 mm2) black wire routed through the driveshaft tunnel and terminated in a 3-pin connection (X4) around the accelerator pedal.
From there, the wires go to the starter and other components, to the ignition switch, fuse box, lighting module, generator, heating system and cigarette lighter contact (X 12/3) in the engine compartment. A capacitor is also installed in the connector (C2) to suppress interference.