M.B.Doc is correct - the vehicle is equipped with the 210 545 03 32 module.

But... is there any way to check the functional status of this module, short of installing a unit of known quality? A new module lists for over $220.


The cycle module's function is not monitored by M-B's HHT but one can easily check for aux. fan activation points:

1) Minimal aux. fan - control current of 2 mA
- engine coolant temp > 95 deg C or
- refrigerant press > 14 bar

2) Maximum aux. fan - control current of 10 mA
- engine coolant temp > 115 deg C or
- refrigerant press > 20 bar

Fan energization voltage can be checked at the module's D1 & D2 pins. And, of course, fan power harness continuity can be easily checked at that point - the harness that plugs into D1/D2 runs straight to the fan motor.

But, if there is no power at D1/D2 and fan activation criteria is met, do the pros do any additional testing? Or do they drop in a new cycle module at that point?