W123 230ce No electric fan

[davidstanton99]

Hi - My first question on this forum as I recently purchased a 1983 230CE

The electric fan isn't cutting in. I'm assuming electromagnetic.

There are two sensors going into the block to the left of the thermostat, a single wired sensor and a double wired. From reading, I gather the two wired sensor connects the fan.

Starting with the basics, I have connected the feed wire to the single wired sensor to a circuit tester and that has a positive feed, however the two wired sensor has no live feed to either wire. So whether the electromagnetic clutch is faulty I dont know as I cant test the sensor as it doesnt have a positive feed. The fuse is fine.

Question. What is the a single relay for, in front of the fuse box?
What is the most likely reason why there is no positive feed to the sensor.

Thank you

 

[BoyracerAU]

What temperature are you conducting your test at?

Welcome to the forum, by the way.

Do post some pix of your car when you get a chance.

 

[millo777]

With an electric fan you should be able to remove the connector on the temp sensor and short out the contacts which will trigger the fan. If you can get the fan running doing this, then it's a faulty temp sensor. If not, then the fan itself is faulty.

 

[davidstanton99]

Thanks for the replies. Sounds like a faulty fan or clutch then as shorting across the terminals in the wire has no effect. If the sensor with the two terminals is the sensor switch to the fan, what it is the single wired sensor next to it?

 

[Dieselman]

Does the W123 have an electric fan, I thought hey were all viscous coupling.

 

[davidstanton99]

Yup - electromagnetic

 

[martyz]

edit

 

[carat 3.6]

Yup - electromagnetic

You mean the fan infront of the radiator, or the fan running off the engine? If it's the one infront of the rad, that should work with the air con switched on. (If you have it?)

 

[davidstanton99]

Theres only the one fan. It's free wheeling when the electro clutch isnt engaged. There is no a/c on my car.

 

[carat 3.6]

Theres only the one fan. It's free wheeling when the electro clutch isnt engaged. There is no a/c on my car.

If you just have the engine fan, it is not triggered electricly. It is a viscus fan which has a fluid clutch, that will only engage when needed. Dose the car overheat?

It should look similar to this

 

[coalville126]

If memory serves me correctly, they have an engine driven fan controlled by an electro-magnetic clutch rather than viscous. It is energised / engaged at 98 deg C. Normally the fault lies in the worn electromagnetic clutch if the OP lives in a warm climate. It could be the thermo switch the engages the clutch which is an easy and cheap swap.

 

[millo777]

Why have you asked for advise on your 124 cooling fan?
I have replied to you,then you post my answer to another thread

anyway does not apply to a w123

The thread title mentions an electric fan, which are very easy to diagnose. Having no experience with the w123, or 4 cyl cars, I had no reason to assume it was actually a viscous coupling in question.

In which case it will be bimetallic strip which switches the fan in and out, with no temp sensor or wires to short etc, hence any diagnosis needs to be done in a rather different way, hence my own thread checking I'm not losing my marbles and about to throw good money after bad changing a part that is less than a year old.

 

[davidstanton99]

I haven't stripped it but was assuming electromagnetic as the fuse box says one of the fuses is for the electrofan. The engine heats right to to the red (120c I think) and the fan does not cut in. It just remains spinning freely

 

[coalville126]

I haven't stripped it but was assuming electromagnetic as the fuse box says one of the fuses is for the electrofan. The engine heats right to to the red (120c I think) and the fan does not cut in. It just remains spinning freely

If you have a single pin fan switch, try earthing it to see if engages. I think yours might be a bit early to have a 2-pin switch, but if it does, bridge them.

 

[davidstanton99]

I have a single pin switch and next to it is a 2 pin switch. The single pin switch has a live feed. When connected to earth the fan doesnt engage. I have bridged the two wires to the pin switch and again to no effect.

 

[davidstanton99]

Carat,,, mine does not look anything like yours which must confirm my assumption that mine is electromagnetic

 

[coalville126]

Just re-read your original post. I don't recall the main fan clutch being relay controlled. Just a basic wire, hot with the ignition on.

Does your car have a/c? There is an auxiliary fan relay for the electric fan in front of the radiator.

 

[carat 3.6]

Dose it look like this pic?

 

[davidstanton99]

Before I start dismantling, is there a relay between the fan and the sensor or is it wired straight through (apart from the fuse that is)

Thank you

 

[davidstanton99]

Carat - no it doesn't look like your latest photo. I will post a photo this evening. Thanks for your help