Radiator Switch vs Water Thermo Switch?

[epoxxy]

I've read this forum from up to down and sideways.
What I've found so far is:

• If you disconnect the cable to the water thermo switch (near thermostat) and the fan starts, the relay is ok.
• If you connect the fan directly to the battery, the fan is ok
• If temperatures doesn't have big differences in upper and lower hose on a hot engine, the waterpump is working.

But what I CANT find is: WHAT is the radiator switch and what is it's purpose?

There should be 2 cables connected to it, and if those cables connect, you can hear a relay click. But it looks like that relay is connected to vacuum hoses.

Please help me to sort this out =)

EDIT:

Found the function of the Water Thermo Swith. It detects the coolant temperature and "opens/on" when above 17C (62,6F).

But why?! What is it's purpose? What happens when "ON" and "OFF" ?

Best Regards - Pelle

[lessersivad]

I think you've answered your own question.

The "thermo switch" breaks contact after it reaches a certain temperature, which "clicks" on the relay and turns the radiator cooling fan on.

IF this is the switch, sensor, sender, you are talking about. It's purpose is to turn on the fan after the engine coolant gets to a temperature deemed hot enough that extra cooling (air through the radiator) is needed to avoid engine damage.

Hope this helps.

[epoxxy]

Oh! I shouldn't be thinking in one language (Swedish) and write in another language (English)

I meant ofcoarse:

Found the function of the Radiator Switch. It detects the coolant temperature and "opens/on" when above 17C (62,6F).

But why?! What is it's purpose? What happens when "ON" and "OFF" ?

The purpose of the Water Thermo Switch i already know, but not the purpose of the "Radiator Switch"
The Water Thermo Switch is near the thermostate, and the Radiator Switch is at the bottom of the radiator.
The "click" heard when the Water Thermo Switch cuts is the fan-relay near the left headlight and starts the fan, and the "click" heard when the Radiator Switch cables is connected to eachother is the relay with vacuum hoses connected to it, and that relay is near the wipers. And nothing happends?

I hope thats crystal clear to understand? Otherwise I'll just scan those pages of the mazda 121 service/repair-manual.


(This time I didn't mix up the switches, but I lost the "edit" button for the first post. *sigh*)

[Festiva Time]

On My '88 Festiva [Carb.] , The Radiator Switch controlled the Radiator Fan and the Water Thermo switch is connected to the ECU for Air/Fuel mixture control.

-Kirk

[epoxxy]

Aaaahhhh. That could be the answer. That's why it's a little unresponsive after the automatic choke has released. (The thingy that makes the engine rev up when cold) And maybe will give me less miles/gallon.

Here's some pictures from the workshop manual:

[IMG]http://dl.dropbox.com/u/1224249/121/1.JPG[/IMG

In first picture; Here you can see that connector no 4 should connect to the Radiator Switch

[IMG]http://dl.dropbox.com/u/1224249/121/4.JPG[/IMG

Here they've renamed the Radiator Switch to Water Termoswitch just to confuse, but you can see that it's still two connectors on it so it really IS the Radiator Switch.

[IMG]http://dl.dropbox.com/u/1224249/121/5.JPG[/IMG

On the last picture you can see that there is a third!? Water Thermoswitch taken from the intake manifold. But this one I don't really have found yet. So the loose cables from the bottom of the Radiator shouldn't be connected to this one

This is how my car is connected, can we sort this out?

[GenevaDirt]

sorry but I had to disable the pics (too large) I removed the end bracket on each string. If you could reset the size to 640 x 480 that would work.

[epoxxy]

Will change the size tonight

[epoxxy]

The size of the pictures is below 640*480 now, but I can't edit my previous posts?

[drddan]

just repost them...

[epoxxy]

Repost



In first picture; Here you can see that connector no 4 should connect to the Radiator Switch



Here they've renamed the Radiator Switch to Water Termoswitch just to confuse, but you can see that it's still two connectors on it so it really IS the Radiator Switch.



On the last picture you can see that there is a third!? Water Thermoswitch taken from the intake manifold. But this one I don't really have found yet. So the loose cables from the bottom of the Radiator shouldn't be connected to this one.

Lets see if someone can sort my cables out

[oneoff]

Hi everyone.

So so glad I found this forum. I have been searching for this answer and right before I post my own thread I found this one... smiling.

I have an 88'. It has a replaced radiator and is missing the famous lower sender. I see on the above post that it also seems to control air fuel ratio.

I get gas mileage like a v8... no kidding. My highway is about 25mpg. It has motorcraft copper plugs ags32c, a carquest tstat and a 4speed manual. Runs great but I bought it to save gas! I might as well jump back into my mustang at this rate.

It has a new coolant sender. My temp gauge takes forever to even move and when driving its always below the first line! Stuck in open look and using more gas??

Do you guys think the radiator sensor is my major issue? Or is that have nothing to do with mpg?

Thanks in advance and great site BTW.

[oneoff]

Anyone?

[creepyjon]

Check the wiring and grounds, the ground cable design is very poor design on these cars. If you have a digital volt ohm meter you should use it to check the wires. I ended up having to rewire my radiator fan and relay because of bad wiring. There is a wiring diagram on here if you know how to read one, it's not too hard. If the computer never sees the engine is at operating temperature it will not go into closed loop, hence bad gas mileage.

[oneoff]

Check the wiring and grounds, the ground cable design is very poor design on these cars. If you have a digital volt ohm meter you should use it to check the wires. I ended up having to rewire my radiator fan and relay because of bad wiring. There is a wiring diagram on here if you know how to read one, it's not too hard. If the computer never sees the engine is at operating temperature it will not go into closed loop, hence bad gas mileage.

Checked the grounds and all good.

Still sucking up gas.