Note: When replacing an independent/additional heater, the tester must first be connected and the "Heater Replacement" function must be called up for the corresponding control unit in the Guided Functions mode. Cable ties and other means of securing the wiring harnesses that were removed or cut off during dismantling must be reinstalled in their original locations during assembly.
Disconnect the battery ground wire with the ignition off. Remove the front right fender liner.
Caution! The coolant in the cooling system is under pressure, the coolant temperature with a warm engine can exceed 100°C - risk of burns. Before starting repair work, release the pressure and let the coolant cool down. Exhaust system components can be very hot. Let the exhaust system cool down before removing it.
Remove the exhaust gas outlet of the stand-alone/auxiliary heater. Place the pan under the heater. Clamp the cooling system hoses with clamps-MP7-602 (3094)-. Loosen the clamps "1" and disconnect the coolant hoses from the pipes. Remove the fuel line from the brackets "3" and "4".
Warning! Fuel may leak. The fuel in the fuel system is under pressure! To relieve pressure in the fuel system, place a clean rag around the connector and carefully loosen the connection.
Plug the disconnected fuel line with a suitable plug. Unscrew the fastening nuts "2" and remove the independent/additional heater from the side member.
Caution! The wires may be strained and the heater control unit "J3S4" may be damaged. First disconnect the 6-pin connector.
Carefully turn the independent/additional heater back, unlock and disconnect connector "1" (6-pin), and then connector "2". Remove the independent/additional heater.
Installation
Installation in reverse order.
Caution! When performing installation work, especially in the engine compartment due to its dense layout, the following instructions must be observed. All types of lines (fuel, coolant, air conditioning) and the wires should be arranged in the original order provided by the manufacturer (using appropriate fastening elements). Ensure adequate clearance from any moving or hot parts.
Install the independent heater and connect the hoses, securing them with clamps "1" and "2". Do not open the clamps. Open clamp "3", disconnect hose "4" and move it vertically upwards. Only when coolant starts to flow out, open clamp "2". Tighten clamp "2" again. Only when coolant starts to flow out of hose "4", open clamp "1". Tighten clamp "1" again. Install hose "4" and remove clamps "1" and "2".
Remove air from the coolant circulation circuit of the independent/additional heater. Query the event recorder, if necessary, delete errors.
Note: If a large amount of air gets into the system during installation, the cooling system should be bled. Follow the procedure for connecting the negative terminal of the battery. If the heater is replaced with a new one, the heater should operate at full load for 10 minutes before handing over the car to the customer. After the first switch-on, grease left over from the factory may evaporate in the parts and units of the heater. The resulting smell may bother the customer, and he will think that the heater is faulty.
(Information copied from the resource: SKODABOOK.ru)