So... What tells the cooling fans to turn on?

[Silverbullet]

So, I replaced the Radiator... and now the fans are not turning on.... It is hot at the radiator, water is circulating...I went through a few cycles... Both hoses in back are pressurized and when cool the expansion tank is about 1/2 full. I got it close to 220 in temp....

Craig

[JETS 81 DMC]

You can test the fans if working by turning on your AC. Fans should run constant when AC is on.

[Chris 16409]

You can also install a jumper wire between the two otterstat wires. That will force the fans to turn on. It could be possible that your ottersat failed the same time of your radiator replacement. It is also possible that you have air trapped in the cooling system.

[Silverbullet]

You can also install a jumper wire between the two otterstat wires. That will force the fans to turn on. It could be possible that your ottersat failed the same time of your radiator replacement. It is also possible that you have air trapped in the cooling system.

Is there a good way to check for air?

[David T]

Yes, feel the radiator on the left and right sides. if it isn't getting hot the pump isn't circulating the coolant. Your bigger problem is the fans not running. Jumper the 2 wires to the "O" switch with a paper clip with the motor running. If that doesn't get them running you must figure out why. If they are running your "O" switch may have failed or you do have a lot of air in the system (or maybe both).

[DMC5180]

The only thing you need to do is pull the radiator air purge line from the upper connection on the passenger side. You only need too pull it back enough to hear the air rush out. You quickly push the hose back on once get the coolant bath[emoji6]

My fans don’t come on via the otterstat Switch until 220. But if you just want confirm the fans are getting power and you have a fully charged A/C system just turn the A/C on . The fans run in parallel with Compressor engagement.


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[David T]

The only thing you need to do is pull the radiator air purge line from the upper connection on the passenger side. You only need too pull it back enough to hear the air rush out. You quickly push the hose back on once get the coolant bath[emoji6]

My fans don’t come on via the otterstat Switch until 220. But if you just want confirm the fans are getting power and you have a fully charged A/C system just turn the A/C on . The fans run in parallel with Compressor engagement.


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That's why running the A/C to test the fans is not a good test. The best test is the simplest one, bypassing the "O" switch.

[DMC5180]

That's why running the A/C to test the fans is not a good test. The best test is the simplest one, bypassing the "O" switch.

Depends on what you’re looking for.
If I want too just check if my fans are getting power, I simply turn the key to run position and flip the A/C switch to max, norm or bi-level. The System is pressurized 70-100 psi static so that tells the clutch and fans to come on even if the the compressor or engine is not running. It’s a matter of key On A/C on and you listen for the Click from the Comp clutch and whirring of the fans. Assuming sound is coming from the fan(s) running I can then put my hand under front too feel for strong air flow from both sides. If I still am not 100 % sure both are running. I you my phone in selfie mode to take a video or photo.

If, you don’t have a known functioning A/C System to begin with, then yes, using the bypass jumper at the O switch is really all you can do confirm fan operation.


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[Silverbullet]

All good... the fan fail wire got pulled out....stays cool now.

Craig

[DMC5180]

All good... the fan fail wire got pulled out....stays cool now.

Craig

[emoji106]


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