| Notes on general repair work on vehicles fitted with auxiliary heater |
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| Disconnect negative and positive terminals of battery before starting electric welding work on the vehicle. |
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| If the coolant has been drained, bleed the auxiliary heater after filling the cooling system → Chapter. |
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| If parts of the fuel system have been removed or replaced, make sure that all components used for diverting fuel to the auxiliary heater are properly installed. Then switch on the auxiliary heater and check operation. |
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| After replacing certain auxiliary/supplementary heater components, switch on the auxiliary heater before handing over the vehicle to the customer and allow the auxiliary heater to run for at least 10 minutes in full load operation. There may still be remnants of factory lubricant for example in or on the components and these would evaporate following initial activation as soon as the components become hot. |
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| If the metering pump conveys gas bubbles instead of liquid fuel to the auxiliary heater (e.g. when braking or accelerating front-wheel drive vehicles manufactured up to 01.03 and with fuel tank only 1/4 full), combustion problems will occur and intense smoke will emerge from the auxiliary heater exhaust pipe → Chapter. |
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| After performing repairs in the area of the auxiliary heater fuel pipe, check that: |
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| The fuel pipes are flush with the bottom of the vehicle and protected against mechanical damage |
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| The fuel pipe to the auxiliary heater is protected against heat generation which could affect operation |
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| The fuel pipe is not making contact with vehicle components which become warm |
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| When performing repair work in the area of the fuel delivery unit, pay attention to correct routing of the pipe for diverting fuel to the auxiliary heater in the fuel tank. If the pipe is not routed properly, the metering pump -V54- may only supply fuel if the tank is completely full (if this is not the case, no fuel is supplied and the auxiliary heater is deactivated on account of a fault). |
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| If there is not enough fuel in the tank (fuel gauge in “red zone”), the control unit in dash panel insert -J285- does not activate auxiliary heating/auxiliary ventilation. |
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