Fans not coming on, thermoswitch?

[Tjp8]

Drove the car today and let it idle and the fans didnt come on, which is weird as they are new, i pressed the aircon button and reduced the cars temps and it was fine.


Tested all relays and they are fine too.

My question is basicly if the thermo switch is faulty will that stop the fans from coming on ?


Thanks
Tj

 

[Spendyrx]

What temp did it go up too?
Lots of people replace the thermoswitch for a mx5 one if I remember rightly because the fd fans come on at like 108c and the mx is 97c.
I'm guessing your fans didn't come on because it didn't reach temp.
Failing that, it could be a failed relay but I'm guessing it'll be that it didn't reach temperature

 

[Tjp8]

What temp did it go up too?
Lots of people replace the thermoswitch for a mx5 one if I remember rightly because the fd fans come on at like 108c and the mx is 97c.
I'm guessing your fans didn't come on because it didn't reach temp.
Failing that, it could be a failed relay but I'm guessing it'll be that it didn't reach temperature

It did reach temp and gauge crept up and overheating, which is weird as ive been driving it loads recently, then parked it up this week and then this happened.

Coolant was checked before i drove it too , so i know that was good.

Once i put the ac on the fans took the temp down to normal operating temp.

Ive checked the relays and they all seem to be working .

 

[Ceylon]

The thermoswitch comes in last on early cars. The ECU has an input before then to bring the fans on. The thermoswitch should never really come into play really.

Anything been changed recently? When you say new fans, are these new OEM fans or aftermarket?

 

[Tjp8]

The thermoswitch comes in last on early cars. The ECU has an input before then to bring the fans on. The thermoswitch should never really come into play really.

Anything been changed recently? When you say new fans, are these new OEM fans or aftermarket?

The fans are brand new from mazda i did the rx8 fan motor upgrade not too long ago and was working perfectly. They work when i press the aircon button but wont come on by themselves anymore.

Nothings been changed recently except it sat for a week in the cold.

The ecu input comes from the coolant temp sensor doesnt it ?

Im assumimg this would cause the car to run rough aswell if it failed but the car runs and drives fine .

Thanks
Tj

 

[Spendyrx]

Maybe worth a look at the temp sensor if its never been changed! I pulled mine out and it literally disintegrated in my hand

 

[Tjp8]

Sooo an update on this,

I jumpered the wires in the diagnotic box and the fans worked.

Just to recap, Fans always worked with ac on but not when the car got up to temp, the gauge went up and started to over heat, this has only just started to happen recently .

Ive just been out and swapped two of the blue relays around for the fans and let the car idle until up to temp,

Now the fans come on, so i waited and it did 3 cycles of the fans coming on.

I tested the relays and they all tested the same so god knows what this cars doing .

 

[Spendyrx]

At least they work now