Radiator fan will not spin - how to diagnose further?

[notenoughmazda]

Hey, I noticed that my 2005 2.0L has been getting pretty hot lately now that the weather is nicer. I am a noob when it comes to wiring, so I think I need some help diagnosing this. The fan will not spin. I tried swapping with a known working fan, and no luck.

Here is what I know:

With the A/C off, and the engine at temp, the fan does not spin up.
With the A/C on, at any temp, the fan does not spin up.
When cruising on the road the A/C is vanilla ice cold
When idling at stop lights, the A/C is cold for a bit, but progressively gets warmer
No check engine has flipped on
Checked the 40 Amp fuse and it looks good.
Coolant levels are good, no leaks observed.

I had a look at the main plug connecting to the fan, and pulled it apart, and it looks brand new inside. On the outside, nothing looks compromised.

There was also another, single wire that was connected to both the fan and then also the fan control panel thing that sits on the fan assembly. This wire was corroded horribly. What is this wire for? (I have attached a pic to clearly show what I mean).




The only things I can think of are that single mentioned above wire, or maybe the relay? How do I check these? Where is the relay even located? I have a multimeter that I borrowed, but I am not familiar with it's operation. How do I get this damn fan working!


Thanks for any help you guys can dish out - I appreciate it!

[Wes08M3]

If I remember correctly, the corroded wire going to the rad fan which causes it not to work is a common problem. I wouldn't even worry about trying to test it, if it's that badly corroded it should be replaced regardless. Replace it and see what happens, most likely it will fix the problem.

[silverstarmazda]

^ +1

but u might want to check if its the plug or the fan that is the problem. connect the wires to a 12v source and see if u can get it going by bypassing the plug itself.

[notenoughmazda]

^ +1

but u might want to check if its the plug or the fan that is the problem. connect the wires to a 12v source and see if u can get it going by bypassing the plug itself.

I'm not quite sure if this is an option? It looks like control module takes a signal wire as well as 12V DC + Ground. Having said that, I did switch in a known working fan, and didn't get anywhere.


Does anyone have a source for where to pick up the electrical connectors for the ground wire?

Also, if the problem was the relay, where would I find it to test it?