I might have found a bug in the firmware for B5.5 with IMMO3 concerning the detection of too low washer fluid level. On my test setup it is not detected by ColorMFA. When I swap the cluster in the setup, with another original cluster, the too low washer fluid level error is given and shown.
ColorMFA firmware version: v2.9.4_b24
Cluster: 3B0 920 829 A (v07)
Cluster coding: 05115 (thus, wash fluid warning is enabled)
I verified the voltage on pin TrInput8 (LED - low wash) in regard to ground.
When pin 6 of T32b (green connector, low wash) is floating (= not connected to ground): 0.7 V.
When grounding pin 6 of T32b, to simulate 'wash level ok', I measure 10.4 V.
Comparing the voltages with the brake pad warning (which is correctly detected) on TrInput2:
When pin 7 of T32b (replace brake pads warning) is floating: 0.7 V.
When grounding pin 7 of T32b, I measure 10.4 V.
I am fairly sure the cluster is ok, since when disconnecting pin 6 from ground, the cluster gives the (loud) beep that you expect when getting the low washer level warning. Only the ColorMFA firmware is not responding to it...
I have checked the electronic schematics in ElsaWin for my car (Passat 3BG, AVF/HCN from 2005), but the wash fluid level sensor is only connected to pin 6 of T32b on the cluster and not connected to CAN-bus:
Please feel free to give me instructions in how to debug this!