By hot weather, My aux fan starts by itself, even when the engine is turned off. Anyone knows why? I had to disconnect it to avoid draining the battery.
Also, when I disconnected the fan, the little plastic socket came apart and now I don't know which wire goes where. On the aux fan side, I have a blue/Black and a brown one, and on the other side, I have a black and a brown wire. Should the brown wires connect together?
The car is a 1988 MB 190e 2.3
Karle
An engine is at its hottest after being shut down. The coolant barely circulates - just by its own heat - yet must absorb all the heat in the cylinder head and block. That's why the fan started running some minutes after the engine was shut down.
Next time leave it as M-B designed it.
The brown wires are the ground and yes, they connect together.
starts often enough so that the battery has
Wait a minute!
You have a Canadian email address.
Its FREEZING in Canada!!
Are you smoking that BC bud and imagining this?
.The fan is controlled by a coolant temperature sensor and a relay. Those are suspect, most likely the sensor is defective.
Aux fan on 201.128 chassis is tripped by the high pressure switch on the a/c reciever/drier. The engine coolant temp fan is an electric clutch fan mounted to the water pump shaft and is tripped by the 100C temp switch . This can not be energized with the key OFF. If you look at the two switches at the drier [ behind the left headlamp], one has spade connectors and the other has 2 short leads and a plug. Unplug the one with the leads. [ The other one is for compressor cut-in] If this stops the fan when it gets hot next time , I suspect the switch , But , I have seen them cut in when the a/c system has been converted to freon 134A and/or over-charged. [ caused by high side pressure reacting to ambient temp] This circuit is alive regardless of key on/off position. This easy test will tell if the fault is in this circuit.
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