Relay Wiring, Negative Trigger Getting Positive While Off
Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=145539
Printed Date: April 25, 2024 at 6:42 PM
Topic: Relay Wiring, Negative Trigger Getting Positive While Off
Posted By: whitefiretiger
Subject: Relay Wiring, Negative Trigger Getting Positive While Off
Date Posted: July 26, 2019 at 11:16 AM
Have a relay wired up to a negative trigger setup to run my cooling fan in my car and while switched power is off I'm getting power back to the thermoswitch.
Relay is wired as follows.
86: 12v in
30: 12v in
85: negative from grounded thermoswitch
87: 12v out to fan
In a nutshell it's putting power to the engine block which is grounded.
I've tried 3 relays and get the same. Do I need to add a diode?
Thanks
Replies:
Posted By: geepherder
Date Posted: July 26, 2019 at 2:29 PM
Yes, you will read 12 volts through the relay's coil. That's the reading you should have. Make sure you fuse your power wires if you haven't yet.
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My ex once told me I have a perfect face for radio.
Posted By: i am an idiot
Date Posted: July 26, 2019 at 9:08 PM
Does 86 have switched or constant? As stated above anytime there is power on 86 you will read 12 volts on the thermoswitch. When engine heats up and the thermoswitch goes to ground it will energize the relay.
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