Both sub and main cooling fan relays clinking out of control!

Hello fello 3geezers, im new to posting because i ussaully find out the answers im looking for, but this time im stuck. Please help, so recently my car overheated and when i looked into why i noticed both my fans (main and sub) were acting wierd. I drove it amd The main fan would not come on at opperating temp and neither the sub after i shut the car off btw everything worked fine before the overheading. I already replaced the fan switch on bottom of the radiator checked all the fuses and jumped the wire to check the relay and fan and sure enough it kicks right up but wont when it needs to. But on top of everything the part that has me stumped is when the car is off and cooled the sub cooling fan relay sometimes clickes on and off rapidly fast and continuesly and causes the fan to turn on and off. So when the clicking started up again i pulled the relay to stop it (it sound like the relay goind mad lol). I turned the key to the on position and the regular cooling fan relay does the same clicking out of control as the other. At this point idk what to do. Please help and thanks

There's also a sensor on the thermostat housing that acts as a fan switch. There's two of them that look identical, but one of them is the ECT sensor for the ECU. I really can't remember which is which, but it'll be the one that doesn't give you a CEL (Code 6) when you unplug it.

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Originally Posted by Samwise

There's also a sensor on the thermostat housing that acts as a fan switch. There's two of them that look identical, but one of them is the ECT sensor for the ECU. I really can't remember which is which, but it'll be the one that doesn't give you a CEL (Code 6) when you unplug it.

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Yea thats the one that controls the sub fan if im correct? Its the only sensor i havnt replaced (replaced ect sensor and fan switch on bottom of rad). Is the small/sub fan supposed to come on when i jump the plug? Because it does not like the main fan does when i jump it, also i already replaced both relays and i am positive both fans work. Couild it be some short of a short or maybe fan timer?? Because relays turn on and off out of control, outta no where sometimes even with the ignition on. Its just a ton of harsh sounding clicks from relays

The on off clicking deal i got once from low voltage. My battery was dead and as I was charging it the relays went wacky. Long shot.

The only time one fan should be running by itself is if the ignition is off and the fan timer decides the coolant's still too hot. Other than that, both fans should turn on at the same time.

I would definitely replace that sensor and see if the problem persists.