Rain Tracker Model: RT-50
Vehicle-Specific Installation Instructions
These instructions apply to these vehicles, which all have similar wiper systems:
BMW 840 94 - 97
BMW 850 91 - 97
Wiring Diagrams and Drawings:
BMW Logic Diagram - Color Scheme 3- also for vehicles with similar wiper systems
Troubleshooting procedure. Print out if needed.
BMW Color Schemes Table - You may not need this.
Wire colors used in this vehicle:
GROUND - BRN
FAST-LOGIC - BLK/GRY
SLOW-LOGIC - BLK/BLU
Special Rain Tracker Installation Notes for this vehicle:
All wires except +12V are available coming from the wiper switch. They
can usually be accessed by removing one or two access panels(Kick Panels).
HOW THE SYSTEM FUNCTIONS
In the BMW system, the stock wiper switch grounds logic lines from the
Windshield Wiper Module (WWM) to cause the system to enter high and low
speed operation. The switch does not carry wiper motor current. When a
Rain Tracker is installed, it grounds appropriate logic lines in parallel
with the switch. Thus, the WWM thinks the driver is simply the selecting
the right speed.
Factory diagrams can often be wrong. If at all possible, use a volt meter
to see which wires from the switch behave as shown. Fortunately, BMW wiper
systems do not vary much. Also, you can check the BMW Color Schemes table
for similar wire colors that might be closer to your vehicle.
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Vehicle data file name: bmw_logic_c3.veh
OEDES makes aftermarket rain sensors and rain sensing automatic wiper control systems for most cars, trucks
and vans.