Hamilton Posted December 23, 2019 Share Posted December 23, 2019 Hi, I'm hoping someone can help me with a recent problem. I replaced the radiator a week ago and since then the small fan next to the main viscous fan is constantly running. It never did this before but now comes on with the ignition. I replaced that fan's control switch at the bottom of the rad but it hasn't made a difference. It's my understanding that the small fan should only come on at 100 degrees. If relevant I also disconnected and removed the air con fan at the very front of the car while I was working around there- it was very rusty and I won't be replacing it (not all Supras have this fan). Just thought I'd mention it. Does anyone have any idea why the little fan is now constantly running? I'd be very grateful for suggestions! Thanks. Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted December 23, 2019 Share Posted December 23, 2019 I'll go with the easy one first, have you tried reconnecting the disconnected air con fan? Quote Link to comment Share on other sites More sharing options...
mellonman Posted December 23, 2019 Share Posted December 23, 2019 when the sensor plug at the bottom of the radiator is disconnected it makes this fan run constantly . I do this to help with cooling on the track for the auto box fyi Quote Link to comment Share on other sites More sharing options...
Hamilton Posted December 23, 2019 Author Share Posted December 23, 2019 I'll go with the easy one first, have you tried reconnecting the disconnected air con fan? I wish I could, but I stupidly got rid of it pretty much as soon as it came out. The connector for the fan is still there- is there anything I can do to the pins to make it seem as though the air con fan is still part of the circuit? Quote Link to comment Share on other sites More sharing options...
Hamilton Posted December 23, 2019 Author Share Posted December 23, 2019 when the sensor plug at the bottom of the radiator is disconnected it makes this fan run constantly . I do this to help with cooling on the track for the auto box fyi I thought as much. My problem is that the fan is running constantly even with the sensor connected. Glad to know it doesn't do too much harm to run it constantly though! Quote Link to comment Share on other sites More sharing options...
Mo Reviews Posted December 23, 2019 Share Posted December 23, 2019 I thought as much. My problem is that the fan is running constantly even with the sensor connected. Glad to know it doesn't do too much harm to run it constantly though! It would probably eventually burn out the motor but I don't imagine it doing much harm in the short-term. Quote Link to comment Share on other sites More sharing options...
mellonman Posted December 24, 2019 Share Posted December 24, 2019 Im pretty sure the sensor is just a temperature switch . You can short out the contacts in the loom plug and this should stop the fan running.if not then you might have a broken wire in the loom or a bad relay. Quote Link to comment Share on other sites More sharing options...
mellonman Posted December 24, 2019 Share Posted December 24, 2019 It is just a switch here is the drawing . Quote Link to comment Share on other sites More sharing options...
Hamilton Posted December 30, 2019 Author Share Posted December 30, 2019 It is just a switch here is the drawing .[ATTACH=CONFIG]234190[/ATTACH] Only just seen this reply- many thanks, really appreciate it. I'll try it. Quote Link to comment Share on other sites More sharing options...
mellonman Posted January 1, 2020 Share Posted January 1, 2020 as you see on the drawing there is a ac pressure switch also in the same line as the coolent switch , if the coolent swich bypass does not work then you will have to check that switch next being its also in the system you have removed . Quote Link to comment Share on other sites More sharing options...
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