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Isolating 2 Negative Input Triggers

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Member - Posts: 3
Member spacespace
Joined: November†18, 2021
Location: Nevada, United States
Posted: December†31, 2021 at 9:07 PM / IP Logged Link to Post Post Reply Quote tctctc
Wiring up electric fans integrating trinary switch and Holley efi - both having negative triggers to activate relay. Need one of the fans to kick on from trinary switch with ac on without feeding signal back to efi ecu, as well being able to kick in fan based on temperature using ground trigger, preferably without feeding signal to trinary switch.
I currently have relay wired up as follows -
30 - 12v constant
87- fan power wire
85 - 12v ignition
86- efi ecu/trinary switch outputs (both ground signal)
Tried using diodes (1N4007 DO-41 ) on both wires from ecu assuming diodes would work with keeping flow in one direction on ground signal vs 12v but doesnít appear to be the case.
Anybody have a simple/straight solution you can recommend? Really donít want to switch my relay input triggers to 12v if I donít have to, only because Iím assuming the trinary switch may not play nice with 12v going to it, however I could be wrong.
Open to any recommendations. Thanks in advance!
Platinum - Posts: 1,355
Platinum spacespace
Joined: August†01, 2004
Location: Illinois, United States
Posted: January†01, 2022 at 1:54 PM / IP Logged Link to Post Post Reply Quote Ween
Banded end of diode connects to the negative trigger/input. Non-banded ends connect to load (relay coil).
i am an idiot 
Platinum - Posts: 13,598
Platinum spaceThis member consistently provides reliable informationspace
Joined: September†21, 2006
Location: Louisiana, United States
Posted: January†02, 2022 at 7:50 AM / IP Logged Link to Post Post Reply Quote i am an idiot
Do not worry about the 12v on the trinary switch. If it is a negative output, it has to be able to accommodate positive voltage on it until it puts ground there.
Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

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