Fuel Fired Booster Heater Water-in-Fuel Sensor

Fuel Fired Booster Heater Water-in-Fuel Sensor

Note! The illustrations in this service information are used for different model years and/or models. Some variation may occur. However, the essential information in the illustrations is always correct.

Preparatory work

Removing components





Remove:
- the engine coolant heater. See: Fuel Fired Booster Heater, B5254T7, L.H.D Fuel Fired Booster Heater
- the combustion preheater module (CPM). See: Fuel Fired Booster Heater Control Unit, B5254T7, L.H.D Fuel Fired Booster Heater Control Unit
- the cover and the pipe couplings. See: Coolant pipe fuel-powered preheater, B5254T7, L.H.D Coolant Pipe Fuel-Powered Preheater
- the cover for the fan motor. It is secured using 4 screws
- the housing around the fan motor.

Important information
The engine coolant temperature sensor (blue cables) and the overheat protection thermostat (red cables) cannot be replaced separately. They must be replaced together with the cable harness and the 14-pin connector.

Removal

Removing the overheat protection thermostat/engine coolant temperature sensor




Remove the 1 screw for the holder.
Remove the sensors from the recesses.
Disconnect all the remaining cable terminals and cables apart from:
- those for the overheat protection thermostat at positions 5 and 6 (red cables)
- those for the engine coolant temperature sensor at positions 3 and 4 (blue cables).
The connector is supplied with the replacement part.

Installation

Installing the overheat protection thermostat / engine coolant temperature sensor
Install the sensors and position the cable harness along the recesses for the heat exchanger. Ensure that the cable grommet is correctly located in relation to the fan motor cover.
Install the holders for the sensors using 1 screw. Tighten.




Install the removed cables together with cable terminals.
- Flame sensor in positions 1 and 2 (blue and brown).
- Glow plug in positions 9 and 12 (white and brown).
- Water pump in positions 10 and 11 (brown and violet).
- Fan motor in positions 13 and 14 (black and brown).

Install:
- the housing around the fan motor
- the cover for the fan motor using 4 screws. Tighten
- the cover and the pipe couplings. See: Coolant pipe fuel-powered preheater, B5254T7, L.H.D Coolant Pipe Fuel-Powered Preheater
- the control module. See: Fuel Fired Booster Heater Control Unit, B5254T7, L.H.D Fuel Fired Booster Heater Control Unit
- the auxiliary heater acc. to: Fuel Fired Booster Heater, B5254T7, L.H.D Fuel Fired Booster Heater.

Finishing

Testing the engine coolant heater
Carry out a performance test of the engine coolant heater. See: Fuel-powered preheater, checking Fuel-Powered Preheater, Checking.