Cooling fans seem strange

[ArmedAviator]

Got a question about my M37's cooling fans. This is my first non-Ford car, so everything is new to me on this...

It seems when the cooling fans kick on, their speed varies noticably up and down. It can go from low to high to low again in 5 seconds and everywhere else in between.

Is this normal operation or a sign of imminent fan failure? Maybe a temperature sensor issue? The engine temperature gauge always seems to stay exactly at 1/3 in the Normal range when the engine is running.

[ArmedAviator]

Here's a video I took of the fans. It's hard to hear with the engine running, but you can hear the fan speed increase and decrease seemingly erratically.

Video Here

[Ilya]

I would think this is fine because they work similar to CPU fans in computers...as the temp goes up, the RPM goes up. If the temp drops, the fan speed drops. Each degree or couple degrees = different speed.

However, one thing you could look at/test is the fan relay. Maybe it's wonky.

[ArmedAviator]

I understand the speed will vary based on temp, that's what PWM is for. But I just find it odd how often it changes speeds up and down (literally seconds) which seems inefficient...or broken which is why I wanted some other peoples' input who have these cars.

[Ilya]

Right, which is why I suggested perhaps looking at something like the relay. Start with the basics.

[mazz]

you may have the "forest air " option which kind of puff a little clean fresh air intermittently
Mazz

[Debonair]

you may have the "forest air " option which kind of puff a little clean fresh air intermittently
Mazz

I think he is talking about the engine cooling fans, not the HVAC blower fans.

[Ilya]

Yes, engine cooling fans which are shown in the video. Number of areas to look at...I believe there is a separate relay for the fan as well as the fan controller itself...