How to modify washer fluid reservoir on the Audi A4 (b5 platform) to support the headlight washer pump and level warning switch for water level.
Positions of new components after the modification:
Washing fluid level warning switch
Check the previous picture for the exact position for the switch. The hole needs to be 25mm wide, I use the wood drill (see the pictures). Simply place the rubber seal on the reservoir and mark the center of the seal. Be careful while drilling to avoid damage to the reservoir. After the hole is drilled, clean up edges.
Headlight washer pump
There is a mark on the water tank at the position where the pump should be mounted. I use a 20mm drill for wood, gently to avoid damage to the reservoir, then clean edges. After drilling and cleaning are done insert rubber grommet for the pump, use some water as lubrication. Then install the pump. Wires for the pump must be at least 2.5mm2. The connector could be the same as for windscreen just connector on the pump must be modified, little notch on the connector must be cut flush.