The fan that doesn’t spin

[bigdog]

relay not getting its trigger signal maybe?

[bigdog]

yes. when you changed the power source to the other battery how did you connect it?

[Babalouie]

On the Luce the fan gets triggered from one of the two temp sensors. The a/c fan wasn't coming on, so I replaced one of the sensors and all was well.

On the NA8 anyway there are also 2 sensors. If it's anything like the Luce, the one at the back of the engine handles the ecu feed and the one at the front of the engine at the thermostat housing handles the fan trigger.

Try wiggling the terminal at the sensor at the front of the engine...if wiggling it makes the fan come on then you need a new sensor.

[Babalouie]

Umm....well I just went down to have a look at the MX5 and I think both sensors are at the back of the engine.

But for what it's worth, here's what the sensor looks like in the Luce


When I wiggled the spade connector, the fan came on and off. Replacing it was pretty easy, just unscrew it and pop the new $30 Mazda one in.

[Garry]

What are you wiggling? The plug that plugs into the sensor on the throttle body (2 wires) is the idle speed controller plug. That shouldn't affect the fan. The other thing with lots off wires is just a connecting plug. If that's what you are wiggling to make it work then it sounds like you have a bad connection in that plug or a broken wire going into it.

I had a similar problem with my main cooling fan, but at the connector mounted on the fan. I pulled the plug to bits and put it back together and it all works as it should again.

Just for a bit of info, if the main fan doesn't work then the A/C fan comes on. I'm not sure if this is an SP specific thing or if all NB's do it.