ATX MKIV #9644 Coyote Build Thread (Index #137) - Trickle Charger Port Added

[topherchrisb]

So tonight I hooked up the orange Maradyne wire directly to battery power, and the fan still didn't kick on. I unplugged the fan connector while it was running and probed the Coyote ECU orange wire - its reading 15.1 V so it's sending power to the fan (this was at gauge coolant temp of around 90°C), the Maradyne controller just won't close the circuit. So I think either the temp sensor is bad (and the Mardyne unit never knows to close the circuit), or the controller is just broken. I'm going to reach out to Maradyne to see if there is any way to test either theory.

You should be able to test both of those situations as well I think. Most temp sensors change resistance as they get warm. Before I put my controller in I hooked up the voltmeter to test resistance and held a lighter slightly away from it. I could then see the measurement sweep as the sensor gets warmer/colder. I think you can also test continuity between ground and your maradyne fan ground wire as the engine warms up. At some point there should be a quick enough modulation or enough contact each pulse that your meter will see the connection solid depending on how sensitive it is.

Oh I forgot too... on mine there is a potentiometer that I can turn that changes how low of a temperature mine will start to come on at. If you have some configuration in your type of unit maybe that's something to look at too? Make sure it's not cranked all the way or something that might cause the signal to start at a much higher temp.