Member Since: 29 Nov 2016
Location: Větrušice
Posts: 5
Instructions for cabin pre-heating of Discovery 3
Instructions for cabin heating setting with independent heating Discovery 3
Conditions:
The author is not responsible for any damage or personal injury caused to the user of this manual. The use is at user’s own risk. The guide is intended for non-commercial use only.
Theory:
This method is not driven by flaps, it only prevents the car with flaps to manipulate after ACC disconnection before hibernation. After switching the ACC on again, the flaps recalibrate. This recalibration is automatic and delays the start of ventilation in normal operation by approximately 10 seconds. Make sure that the battery is fully charged and in good condition.
Interruption of the flap control can lead to error notification in DTC. It may be ignored. The ventilator is controlled by switched relay in BJB, followed by sending control voltage into the ventilator resistor. Ventilator speed can be controlled by the controlling voltage magnitude.
Suitability of use:
This user guide is intended for Discovery 3 with fully functional webast and for an inbuilt system for activation of the webast as independent heating. It is possible that the user guide works also for cars with identical air conditioning unit as D3 (RRS, FL2). Nevertheless, this has not been tested. The guide is not intended for vehicles with PWM ventilator speed controlling.
Flaps setting procedure:
1) Before switching the engine or ACC off, set the air-conditioning unit as follows:
- AC on
- Switch on interior recirculation
- Temperature to 28°C
- set direction of blowing to the windshield for de-icing
- set the blow towards your feet for better heat-up
- we recommend combination of these two settings
2) Stop the engine and pull the key out of the ignition box
3) Switch the button over to webasto position (must be done within 30s before the car sets the flaps into initial position)
4) When the cabin is heated and before restarting, switch the button back into position “normal”. Insert the key into the ignition box. If you forget to do so, it is necessary to stop the engine, switch the button and start again.
Assembly:
1) Prepare the bundle of cables with a switch and relays. Mark the Normal and Webasto position on the switch.
2) Install the switch with the bundle into the car, for example in the upper glow box.
3) Dismantle the A/C unit from the central panel (do not disconnect the connectors). With help of the multimeter measure the voltage on C1630-PIN17 at all ventilator degrees. Measure the voltage against GND, for example C2655-PIN3 B (ACC must be switched on to make sure the ventilator is working, the engine should be off). Voltage range during the ventilator operation should be approximately 2-3 V, after switching off 0V and at the maximum speed 9-12 V.
4) Adjust the output voltage on stepdown module to mean value, for example 2,5 V. Then install the module in prepared bundle and connect all conductors according to the wiring diagram. Do not forget to add the diode in circuit fan volt sens. If not, in normal mode, the step down module will lead away the voltage of ventilator control and it will not start operating! I placed the module using screws next to the upper glow box under the case of the central console. It is recommended to place the module so that you can easily change the speed settings of the ventilator.
Click image to enlarge
5) The first activation:
Set the switch to normal position. Turn on the ACC and set A/C unit according to prescribed method in the beginning of the user guide. Turn the ACC off and take the key out of the ignition lock. The switch must be switched over to webasto position within 30 seconds (before the car sets the flaps into initial position).
Start webasto now. If you followed the instructions correctly, you should be able to hear the ventilator now. Regulate the ventilator speed to slow. Excessively fast ventilator will conduct too much heat and webasto does not manage to warm up the engine and the cabin. You need to try and select the best option for you.
Comments:
- In case you use a different method for webasto activation other than oval timer, it is necessary to find out if there is an output for relay.
- If not, a GSM module or RF remote control must be used (or equivalent) for activation.
- This is a simple way to make the device. It is possible to use relays instead of the switch and control with +12V ACC voltage (the switch must be kept for summer operation).
- Including a time relay in the circuit and switch on the ventilator with delay are good options.
Connectors details
- C1630
- C2655
Click image to enlarge
- C1629
Click image to enlarge
And finally, I would like to thank Lena Titěrová for her help with the English translation.
22nd Jul 2022 1:15 pm
pwheeldon
Member Since: 15 Jan 2020
Location: West Yorks
Posts: 1461
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