190e 2.3 8V Aux Fan Issue - PeachParts Mercedes-Benz Forum

denaliano · #1 08-15-2012, 04:11 PM

Having some high temp issues when AC is on, and noticed that the Aux fan isn't coming on when the AC is running. So I attempted to manually engage it.

When I short the aux fan/pressure switch on the condenser, I hear and feel the relay click inside the fuse box, but no fan.

So then I ran a heavy gauge wire from the battery to the Aux Fan Pre-Resistor and it kicks on LOW speed. Good, that's normal.

My question is, now why isn't it kicking on when I trip the switch and activate the relay?

When I short the High Temp sensor on the head, the fan kicks on, so the relay is working, correct? Attached wiring schematic.

denaliano · #2 08-15-2012, 07:57 PM

Just responded to a PM from a member who suggested Fuse 3. I'd love any other input!

Quote:

Thank you! The fuse was not blown, and I passed over it. But upon pulling it, I found that it was "stuck" almost as if it had melted in place. Once I cracked it out, and replaced it with another 16A i was able to short the wires that trigger the relay and the fan came on.

But now still... It won't kick on when the AC is on. Right now I have those wires connected and the fan runs on low whenever the car is running. I drove home in heavy traffic, and the temp stayed around 80ºC AC on or off.

So, could this mean a faulty pressure switch on the condenser? Could I be low on freon?

If I swap this switch out, will I lose all my freon? R134A has gone way up in price!

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