C 320 CL (203.764) V6-3.2L (112.946) (2004)
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Models 203, 209
fuse 35 in the interior fuse box.
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Models 215, 220
fuse 41 in the right fuse box.
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Model 230,
fuse 56 in the rear fuse and relay module.
Flame-Out/Flame Monitor Malfunction During Heater Operation
Flame-out/Flame Monitor Malfunction During Heater Operation, Function
Shown On Models 215, 220
Operating procedure
1
Coolant temperature > 65 degrees C and < 77 degrees C
2
Depending on heat requirements, the STH heater or heater booster operates in partial-load or full-load mode:
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The STH or heater booster fuel metering pump (Y23) and the combustion air blower (A6m2) deliver at their minimum or maximum speeds
and outputs.
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The coolant circulation pump (A6m1) delivers the coolant via the heat exchanger (2) and the heating and cooling circuits.
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The vehicle blower feeds pre-heated air into the interior.
3
In its function as flame monitor, the flame monitor heater element unit (A6r4) continuously monitors combustion in the burner housing (1).
4
The flame monitor glow pin unit (A6r4) signals:
"cold" = flame-out because of lack of or inadequate fuel or combustion air supply
or
"cold" = glow pin malfunction in flame monitor glow pin unit (A6r4).
5
The STH or heater booster control module (A6n1) initiates a start attempt for approx. 85 s to light a new flame and start the combustion process: