Disconnect the ground wire from the battery.
Remove the control box cover. The control unit is located in the right rear of the engine compartment on the bulkhead under the windshield.
1 - DDE control unit;
2 - glow plug relay
Press the locking hooks on the left and right and remove the relay.
Check the strip fuse next to the connector and if it is defective, replace it. Before doing this, identify and eliminate the cause of the overload.
Unscrew the thick positive wire from the top side of the relay housing.
The figure shows a diagram of the preheat relay. The location of the connection contacts is shown on the cover of the preheating relay.
G1...G6: Glow plugs 1...6 (Four-cylinder engine: 1...4);
KL 15: from the ignition switch
KL 30: battery plus
Ust: voltage from the DME control unit
Dia: diagnostic contact
Connect the battery and connect a voltage tester to terminal 15 and ground. Turn on the ignition. The probe LED should light up, otherwise check the electrical connection to the ignition switch.
If the LED lights up, check for open circuits in the wires to the glow plugs and replace if necessary. Otherwise, replace the preheat relay.
Install the control box covers and engine linings.