Ford Workshop Service and Repair Manuals

The booster heater is for vehicles with a diesel engine.

The booster heater is mounted centrally on the bulkhead.

On vehicles intended for countries with a cold climate, a fuel operated booster heater is installed, and this can also be ordered as an option.

The electrically operated glowplug booster heater is integral with the cooling system and is switched on and off depending on certain pre-conditions.

The glowplugs are controlled through 3 relays by the PCM and are switched in three different stages, depending on demand.

• 1st stage: glowplug 1 is activated
• 2nd stage: glowplugs 2 and 3 are activated
• 3rd stage: glowplugs 1, 2 and 3 are activated

The glowplugs are activated under the following conditions:

• Cylinder head temperature below approx. 75 °C
• Intake air temperature below 5 °C
• The generator has enough power in reserve

Relay locations

The relays are located in the fuse box in the engine compartment.

Fuel-fired additional heater

Description of Operation

The fuel operated booster heater is for vehicles with a diesel engine in cold climates.

The booster heater is integral with the cooling system.

At the maximum level it provides up to 5 kW heating power to the coolant.

All start and control functions and the run-on functions to cool after switch off run automatically.

Safety devices monitor the operation of the booster heater.

A fuel metering pump which is mounted on the booster heater provides it with fuel from the supply line to the engine.

The combustion air is taken in from an area protected from water spray, in order to guarantee operation of the booster heater in all weather conditions.

The booster heater has its own exhaust system which vents safely into the atmosphere.

The external temperature sensor prevents boost heating when the ambient temperature is above 8 °C (no boost heating needed). The ambient temperature sensor is located at the right, on the radiator bracket.

Coolant flow

Coolant flows as follows: engine - EGR - booster heater - heat exchanger - engine (no EGR in Turkey).

Switch on conditions

The following conditions must be satisfied before the unit will start:

• 12 V from generator (terminal 61) (generator voltage when starting must remain at more than 11 V +/-0,5 V for longer than 5 seconds. The switch off signal is set at 8 V +/- 0,5 V in order to avoid the unit switching on and off during operation.)
• Terminal 15 (ignition is switched on)
• Battery voltage (terminal 30) and ground (terminal 31) must be present at the control unit of the booster heater
• Coolant temperature below 75 °C
• Ambient temperature below 8 °C

Operation sequence during first start (125 seconds)

Before the first start of the booster heater, the operation of the individual components is tested.

This operational test consists of:

• Control unit check
• Flame sensor
• Control sensor
• Overheating sensor
• Glow plug
• Fuel pump
• Blower motor

The booster heater will only start after the self test of the heating unit is successful.

Should a fault be detected, a fault notification will be output through the vehicle diagnosis.

The ceramic glowplug starts to heat the combustion chamber.

After a delay, the blower switches on. During the start procedure, the blower continuously increases blowing power.

The fuel pump pumps fuel into the combustion chamber. The cycle frequency of the fuel pump is also continuously increased during the start procedure.

The glowplug starts to vaporise the fuel, and creates the necessary temperature for the fuel to ignite.

Once the booster heater is working, it runs continuously rising to maximum heating power.

After the flame sensor has detected the flame, the start process is complete, and the glowplug switches off.

Second start (125 seconds)

If the first start is not successful, the heater commences a restart process. In doing this, the glowplug voltage is increased, in order to obtain better starting conditions.

For the second start, the first start sequence is then repeated.

Unsuccessful second start

If the repeat start (second start) is not successful in igniting the heater, a fault code is output from the heater (safety time exceeded).

A new attempt to start will only then occur after the engine has been switched off.

After 10 failed starts (first start, second start) one after the other, all further start attempts are stopped by the control unit. This inhibit state can only be released by clearing the fault memory.

Run-on mode (120 seconds)

After the coolant has reached a temperature of 85° C or the switch-on conditions are no longer satisfied, the heater passes into run-on mode.

In run-on mode the combustion chamber is cooled and prepared for a new start.

The glowplug and blower motor are activated.

Temperature control of the booster heater

The control stages of the heater are determined by the coolant temperature.

The coolant temperature however depends on the amount of heat supplied by the engine and by the booster heater.

Boost heat control depending on coolant temperature

• up to 80 °C: 5 kW (max. power)
• 80 °C to 85 °C: 2.5 kW (50 % power)
• over 85 °C: 0 kW (off)
• 75 °C: restart

Safety devices of the booster heater

After a failed start (unsuccessful first and second starts) the following fault notification results: safety time exceeded.

If the flame extinguishes after flame recognition, the heater remains operationally ready, as long as a restart is still allowed, if the second start is successful the fault code is cleared.

If no more repeat starts are allowed, the heater outputs the fault notification: Flame out.

If the temperature at the overheating sensor exceeds 125 °C the following fault notification is output: Overheated.

If the voltage supply to the heater remains below 10.2 V for a time >40 seconds, a "Low voltage shutdown" is notified.

A fault during self test causes the start process to interrupt and generates a fault notification corresponding to the fault which occurred.

Block circuit diagram

Parking heater

Description of Operation

A parking heater is optional, and only available with a diesel engine.

It takes over the function of the booster heater and mainly corresponds in its operation to the fuel operated booster heater.

Additional components are the coolant pump and the mini-clock (control) In addition the control unit has extra functions.

The parking heater is controlled through the mini-clock. The booster heater functions follow automatically.

Start procedure: The coolant pump of the parking heater starts, and after a flush and pre-glow process, combustion is initiated by the combustion blower, glowplug and fuel pump. If the flame is stable, the glowplug is switched off.

The safety devices correspond to those of the fuel operated booster heater.

Like the booster heater, the parking heater is built into the cooling circuit.

Coolant flow

First of all the parking heater warms the coolant for the vehicle engine.

After the engine has been heated by the coolant, the heat is passed to the vehicle interior, depending on the blower level chosen.

Adjustment functions of the mini-clock

Initial setup:

After connecting the current supply, all symbols will be shown flashing in the display.

The parking heater cannot be turned on in this state, the current time must first be set:

• Press button 6 - time flashes. Set time using buttons 5 and 7.
• Press button 6 - current time is shown, colon symbol flashes.

Set current time:

• Press button 6 for longer than 3 seconds, current time flashes,
• Set time using buttons 5 and 7,
• Press button 6 for less than 5 seconds - current time is shown, colon symbol flashes.

NOTE:If button 6 is not pressed after setting the current time, the system enters "Set heating time" mode.

Set heating time:

• Press button 6 for longer than 3 seconds, current time flashes,
• Do not press any buttons, the mini-clock switches into "Set heating time" mode (symbol for heating operation and heating time flash),
• Adjust heating time (10 to 120 minutes) using buttons 5 and 7.
• Press button 6, current time is shown, colon symbol flashes.

Set preset time

• By pressing button 6 once, twice or three times, preset time 1, 2 or 3 is called up. Shown in display e. g.: preset time 1.
• Set preset time with buttons 5 and 7.
• The preset time is activated or deactivated using button 4.
• When preset time is activated, the symbol "ON" (2) is displayed.
• When preset time is activated, the symbol 1, 2 or 3 is displayed.

Operating functions of the mini-clock

Switch on parking heater:

• Press button 4. Heating time is . . . . . minutes. Shown in display: remaining heating time and symbol 3 heating operation

Switch off parking heater:

• Press button 4. The parking heater runs on for 3 minutes. Shown in display: current time.

Continuous operation:

• Press button 7 and keep it depressed, then press button 4. The parking heater is switched on until button 4 is pressed (switch off parking heater).

Activate/deactivate preset time:

• Select preset time 1, 2 or 3 by pressing button 6.
• The preset time is activated/deactivated using button 4.
• When preset time is activated, the symbol ON is displayed.
• When preset time is activated, the symbol 1, 2 or 3 is displayed.

Block circuit diagram