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Odd prewire in a W203. Heated water hose and Thermotronic pollution sensor

miro

MB Enthusiast
Joined
Mar 1, 2004
Messages
3,444
Location
Sydney NSW Australia
Car
W203 slightly modified
A while back there was thread on Thermotronic upgrading using all of the necessary parts. In the process of poking around my car I discovered two things.

- Heated hose prewire = which consists of an unused thermistor coupling connector at the wash bottle.

- Pollution sensor prewire = which consists of a spare connector near the battery under the wiper splash barrier.

One harness runs as follows.

- Pollution sensor
- Airconditioning sensor (at front bumper)
- Ground
- FRONT fuse box connector
- Hot water pump power connector (other side)

The heated hose connector is part of the main engine bay harness (runs around the outside) and is connected to the wiper washer system.


THERMOTRONIC UPGRADE NOTES
==========================
Those persons tempted to do a full Thermotronic, if you have the pollution sensor prewire then all you need externally is the sun-sensor wiring.

I will provide some images and information in greater detail later.

It would save quite a lot of time to be able to just bolt on the external items as the Sun Sensor wiring takes little to install once the barrier is removed (which needs to be done anyway to install the pollution sensor module).


The inboard stepper motor upgrades can be done to ANY W203 as the 581 upgraded heater box is IDENTICAL. They use levers to mirror the left and right side in AIR CONDITIONING and in the THERMOTRONIC they use extra motors.

The blower motor housing (which can be removed) is the only item which needs to be exchanged for THERMOTRONIC as the new housing requires a stepper motor and a set of carbon filters.

Just some thoughts on the Thermotronic upgrade. If you are having the dreaded "click of death" on your A/C then consider having all of the cogs replaced and maybe also having the upgrade.



HEATED WINDSCREEN WASHER
=========================

The heated water hose is part of the Heated Windscreen Washer. In a right hand drive car it is amazingly simple to install.

- 6L washer bottle ( and some plugs for unused ports)
- heated water coil with grommets
- hose adaptor from heat exchanger (sits under wipers)
- coolant water pump with 3rd outlet
- tube which installs under front bumper
- heated washer jets (normally installed on a W203)
- washer jets supply hose with thermistor
- brackets to hold hoses in place and some clamps

If you have REST on your AC then you already have the other parts. If your bumper is removed it takes about 3 hours to install.

requirements
- heated windscreen jets
- REST on your AC.
 
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