Labscope testing a cooling fan motor

If you suspect the cooling fan motor is bad, you can use your labscope to confrim it just like you would a fuel pump. After all, they are both electric motors. All you have to do is isolate the circuit and use a low amp current probe.

Category:

Autos & Vehicles

Tags:

• labscope
• auto
• repair
• cooling
• fan
• motor
• diagnostics
• testing

[studpuppy69]

Dwayne, you said the old motor was pulling too many amps at 14.*, the new fan pulls 15.* plus. Could you explain maybe I mis understood. Great vid thanks.

[bgregg55]

Its all about having great tools & knowing how to use them. Thanks for another great vid.

[qloopp]

You set your ESI probe to the 20 amp AC setting. Should've used the 20 amp DC setting for an accurate reading. 14.9 amps isn't "way too many amps" for that fan motor. The reading, even when taken properly, is also dependent upon available voltage.

[drotimes4]

i dont get it , whats the difference between the new fan and old, if the old on was still working, i dont see why it would cause it to overheat, maybe lower amps- less rpms but i dont think that would cause the engine to overheat

[xxioryyagamixx]

interesting the use of the scope for coolng fans but, want it drawing the same amount of amps??

[precopster1]

Hi Duane, great job in diagnosis, it's mazing what great tools can achieve. Noticed the amperage thing, too. The new one actually drew more; poor design of new motor?? Your circuit breaker probably tripped because of a non-DC pattern waveform; not excessive current. What is the fuse rating on circuit to the fan? What is the wattage of the fan? It should be 210W or thereabouts, no more. If it's rated at 150W the new fan is overdrawing. Good luck.

[midlantic1]

I noticed that as well. Still pulling 15 amps?

[sdeery]

Just so everyone knows, his name is Duane.

Good video by the way.