Ralph Whitaker Posted November 24, 2020 Report Share Posted November 24, 2020 (edited) Need to put a relay on the electric fan, as turning the ignition off with the fan running does not switch off the engine cleanly. I suspect the fan motor becomes a dynamo and keeps back feeding the ignition circuit. At the same time I would like to put in an overide switch. I`m thinking permanent live to relay to power fan, maybe from solenoid with an inline fuse. Switched power from ign to one side of thermostatic switch, then from thermo switch to relay operating circuit, with another switched feed from ign direct to relay for overide. Does that sound right or have i missed something? Ralph Edited November 24, 2020 by Ralph Whitaker Additional thoughts Quote Link to post Share on other sites
harlequin Posted November 24, 2020 Report Share Posted November 24, 2020 I have a permanent live to the relay which is looped to feed the switched live to the fan. The thermostat then switches the relay earth with an alternative switch on the dash for the relay earth. George Quote Link to post Share on other sites
Graham Harris Posted November 24, 2020 Report Share Posted November 24, 2020 This is how you need to wire the fan Graham Quote Link to post Share on other sites
RogerH Posted November 24, 2020 Report Share Posted November 24, 2020 Hi Ralph, this is my version but much the same as above Roger Rad Fanxxx.docx Quote Link to post Share on other sites
harlequin Posted November 24, 2020 Report Share Posted November 24, 2020 1 hour ago, Graham Harris said: This is how you need to wire the fan Graham A picture saves a thousand words! My version is the same as Graham's except I have a jumper lead between terminals 85 and 30 instead of a feed from the ignition. That way the fan often kicks in when you turn the engine off and the hot water rises in the rad much like a modern car. In addition to the thermostat switching the 86 to earth I have a manual over ride but have never found the need to use it George Quote Link to post Share on other sites
Ralph Whitaker Posted November 24, 2020 Author Report Share Posted November 24, 2020 Thanks for the replies chaps, I will obtain a relay and set to this weekend. Ralph Quote Link to post Share on other sites
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