Testing Fan Motor

[dancnman]

My radiator fan motor blew a fuse and stopped working today. I jumped it out at the thermo switch to ground and nothing happened.

I put another motor in and it doesn't work either. Fuse is good and power is to the fuse itself.

So, what else might need looking at?

Also, the thermo switch wire that grounds to turn on the fan, is it a ground wire that will show continuity when checked to a ground with a meter?

[WintrSol]

The thermo switch should only connect to ground when the coolant temperature is high enough; I haven't found that temperature in the manual, but my fan turns on about 200-210F. When the coolant is cooler than that, you should read battery Voltage at the wire that connects to the thermo switch from the fan (when the key is on, of course). Between the blown fuse and fan not running when grounded after replacing the fuse, I suspect the power wire to the fan is damaged, and momentarily shorted to ground before it opened up. Trace the wire back to the fuses, looking for a damaged spot, probably where it goes around a corner.

[dancnman]

Is the thermo switch part of the ground circuit. Should it have continuity to the battery/ground? I don't know which wire I need to trace and verify. I don't have continuity to ground at the switch wire. I am thinking I should have but I am not sure.

[Savago]

I had to replace my I/S fan, but later identified that the fuse was bad.

Here you should find some photos of when I had to test it (using a voltmeter to read the power at the fan and also grounding the sensor):
https://plus.google.com/+AdenilsonCavalcanti/posts/b4sBMSadEv2

[dancnman]

Thanks

[indybobm]

I responded to the post in the General Section before i saw this one.

The only time you will read resistance to ground at the thermostatic switch is when the engine is at the temperature to turn on the fan, around 200 degrees (199-207).

If you disconnect the fan wire from the thermostatic switch on the radiator, you should have 12VDC between that and a good ground. This checks the voltage path from the battery through the ignition switch, the fuse, and the fan motor itself. If you do not have 12VDC at the wire, trace back along the path to see where you loose it.

There is a seperate wire from the ignition switch that feeds the fan fuse through a blue-orange wire at the 4P White connector under the gas tank. If you do not have 12VDC at the fuse, I would suspect the ignition switch.

[dancnman]

I responded to the post in the General Section before i saw this one.

The only time you will read resistance to ground at the thermostatic switch is when the engine is at the temperature to turn on the fan, around 200 degrees (199-207).

If you disconnect the fan wire from the thermostatic switch on the radiator, you should have 12VDC between that and a good ground. This checks the voltage path from the battery through the ignition switch, the fuse, and the fan motor itself. If you do not have 12VDC at the wire, trace back along the path to see where you loose it.

There is a seperate wire from the ignition switch that feeds the fan fuse through a blue-orange wire at the 4P White connector under the gas tank. If you do not have 12VDC at the fuse, I would suspect the ignition switch.

Thank you much.

[Savago]

I confirm what indybobm said i.e. with the bad fuse, I had no voltage at the plug in the colar where the fan is connected. Changed the fuse and then had voltage.

In case you don't still have one, you will need a voltmeter. At the time I bought one for 16bucks, brand was Etekcity MSR-R500 and it is a quite useful tool for diagnosing issues.

For testing the wiring from the  fuse all the way up to the colar/plug, you may need piercing test clips: https://www.amazon.com/gp/product/B013ARWXTU/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

[WintrSol]

Is the thermo switch part of the ground circuit. Should it have continuity to the battery/ground? I don't know which wire I need to trace and verify. I don't have continuity to ground at the switch wire. I am thinking I should have but I am not sure.

The thermo switch gets ground through its case, when it is screwed into the cooling system. Its only terminal goes to the fan.