2012 Lexus IS250. Should both of the fans on the Radiator Dual Cooling Fan assembly always be spinning?

The passenger side fan spins for a few mins then it will stop then start back up again shortly after. The driver side fan I haven't seen spinning at all......

This is the part I am talking about https://www.1aauto.com/2006-13-lexus...BoCpXUQAvD_BwE

 

Left side is the AC fan. Will be on when your AC is on. The right side is the cooling fan. It will only come on to cool the system down. Which in turn is about 205F degrees.

If you want to test the cooling fan. After a drive park the car, and turn off the AC. Pop the hood and remove the radiator cover off the front. The fan should come on shortly while idling. It will kick on at about 205F then when it comes on. The temps will drop to about 185F.

 

By left side do you mean driver side or passenger side??

And the spinning, stopping then spinning again is that normal? This happens on the passenger side fan.

 

So I turned the a/c off and let the car heat up. Both fans stayed off then the passenger side fan kicked in after 5 or 6 mins. Then turned off again.

The driver side fan again never turned on when testing with A/C off and A/C on.

 

All references are from the drivers seat looking forward.

At highway speed on level ground w speeds above 35mph, typically no fans are required with the AC off. So if you pull off swiftly and look there will be no fans. Switch on the AC and left fan will come on and depending on the differential temperature and engine temp, the right fan.

 

The fans for cooling the engine is thermostatically controlled and will normally switch on and off. When the coolant temperature reaches approx 205º F, the fan turns on. When the fan cools the coolant down, the fan will shut off.

 

Okay so driver side is the cooling fan. That's the one that's not coming on

I got some 12v test leads and the passenger (right side) fan still worked when connected to the leads but the driver side (left side) didn't work.

So this means the motor on that side is broken right???

 

No. You have a US car. From the drivers seat looking forward the fan near the air box (right side) cycles off/on for coolant control. The left side when the AC compressor is active.


Let's back up. What seems to be the problem?
Does your engine overheat? Does coolant spill on the ground? Does the AC blow cold air?

 

Engine gets hot but doesnt overheat. Temp gauge stays in the middle. No coolant spilling on ground and I just refilled coolant and recharged a/c as both were low. A/C isn't as cold as it should be and the passenger side vents in the front blow warmer than the driver side vents.

Right side fan kicks on and off like you're saying it should. Left side fan never turns on. I tested both sides with 12v test leads and the left side still doesnt turn on

 

Good info that lets us know where you're headed.

Disconnect the fan that doesn't turn on and place a 12v test lamp into the car side of the cable. Turn on the AC (engine on). See if lamp turns on. It's not much of a test but if the lamp comes on, it points the finger at the fan as the fault.

If you have a 65 watt headlamp laying around and can safely connect that in place of the fan, that's nearly a 5Amp load if the bulb grows bright when powered and could provide a warm fuzzy the circuit works!

 

Tried the test lamp. No fan spinning still.

 

So applied 12v to this fan and it does not operate. If yes, motor is bad.
What happened with the test lamp and AC on? Did it light?
If no light, check the fuses and relay. I'm guessing you could temporarily swap the relays.

If you closely at the relay function and pin out, you could also jumper the input to power the fan.

On the bad fan did you measure the input resistance?
Side note: with these being brushed DC motors, a GOOD motor acts as a generator and will produce voltage if spun.This would be another simple test to say yes, fan is bad if it produces no output when spun or shows infinite resistance. On that note; if it shows a dead short, the fuse or relay upstream are likely bad.

Make sense?

 

Will check the relays sometime this afternoon. Is there 3 of them I need to look at? Are all 3 in the fuse box under the hood on the driver side of the vehicle? It's a 2012 IS250 if that matters.
How do I know if they are bad?

 

With engine & AC on did the lamp light where the fan plugs in? If no then you need to investigate. If yes, you're are likely fine but this hasn't been answered.

 

No man I already said it didn't.