Fan switch for 1989 W124 230CE

[White230CE]

Hello all,

I'm new to this forum, new to W124 ownership and new to car DIY! Just bought a 1989 230CE as an introduction to W124 ownership. So far, I've learned lots just from reading previous posts, so thanks to all those authors.

I now have my very first question. My car tends to overheat in slow traffic, and thanks to previous posts, I have concluded that most probably, the fan switch needs replacing. As this is the aircon model, I have found out from MB that I need a two pin switch, MB Part No. 008 542 45 17, quoted at £25.

The corresponding part from GSF which is stated to be for the W124 230CE M102 engine, is GSF Part No. M93460 and costs £7.48.

However, GSF have a different MB Part number correlating to this part, and they say it's possible that they haven't got the updated MB Part number that I've got. Can anyone please tell me if the GSF part is the correct one?

More importantly, when I went to change the switch, there are two two-pin switches in the engine. One in front has red plastic and wire attached, the other has blue-green plastic and wire attached - see Pic.

Which one is the fan switch, and what does the other two-pin switch do? With the engine on, I pulled each one off in turn, hoping to see some reaction, but all the gauges, including temp gauge, continued to show readings.

Please help!

Many thanks

White230CE

 

[television]

Hello and welcome to the MB forum.

Without too much searching on this, and without knowing if the car has a visco clutch or electric.

Re the 2 switch sensors, they do fail and quite a few post on those in the last year.

These are switches , so pulling the plug off the top will not do anything, to test them you need to pull off the plug, and with ignition on take a short piece of wire and short out the 2 pins, this will start up any fan, and you can do no harm.

We do not know your fan type, with the visco fan, it should cut in at 80ºC you should hear the metallic click as it cuts in and speeds up.

Any electric fan cuts in at 100ºC, so the thing is to run the engine, see what happens from 80C on, and then up to 100ºc to see what comes on.

If you have an electric fan on the engine, there should be two wires coming out of the rear, and one goes up to the switch in the top of the engine that you have in the picture

 

[White230CE]

Hi Malcolm,

It's an electric fan as far as I know. At the moment, it works intermittently - sometimes the gauge will go up to 100 then drop to a steady 80 ish, from which I guess the fan is switching on; other times it will go up to 110 and stay there, at which point I cut the engine to avoid damage.

I will try shorting the pins to see what happens. I will also see if I can trace the wire from the fan to the switch.

Thanks for your advice.

Ray

 

[television]

Ray it should be the one at the front on top, easy to test by shorting out the wires

 

[White230CE]

Thanks very much Malcolm. I shorted the wires and yes, it was the front/top one in the picture. Replaced it and engine now stays at the right temperature.

The switch from GFS was the right one, despite not having an up-to-date MB Part number. Cost me £7.80, compared with MB's price of £25, so very chuffed!

Now for the SBE - as per other thread....