Electrical E-fan indicator lights

foxbodybill89

Member
Jan 19, 2020
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4
13
31
Sioux Falls, SD
I put in a Contour fan setup and Dakota Digital controller, and wanted to have some indicator lights on the dash just to monitor the operation mostly of the controller. I wired an automotive LED indicator in series with the ground trigger wire to each relay (high and low fan speed). When I tested the controller the dash lights worked as they should but the relays wouldn't trigger. So I bypassed the lights and the relays worked fine. Are the lights not letting a strong enough ground through to trigger the relays? Can I wire the lights in parallel somehow with the trigger circuit instead? I don't really want to tap into the big fan power wires like I've seen elsewhere I just want to monitor the switching of the relays by the controller.
 
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Blown88GT

Founding Member
Nov 13, 1999
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Palm Beach Gardens, FL
The LED's need to be placed across the fan motors. When the motors turn on, the LED's will light up.
Relay pin-87 to ground is the same thing.
This is a configuration for 1 fan with 2 relays, the 2nd relay is for the A/C.
FanControl.jpg
 
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foxbodybill89

Member
Jan 19, 2020
27
4
13
31
Sioux Falls, SD
That's what I was afraid of, I've seen most of them done that way but I wanted to try to do it without disturbing the big power wires. I'm going to try to wire the lights in a parallel circuit to the signal wire and see how it works.
 

KRUISR

Well-Known Member
Apr 16, 2015
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I have lighted toggle switches wired in parallel to the temperature switch that turns on each speed. The toggles can manually turn on each speed but also light when the temperature switch turns on the fans.

Lighted toggle switch.jpg Interior toggles.jpg

It doesn't let you know if the relay craps out or if the fan motors are actually turning, just that they are supposed to be.
 

Blown88GT

Founding Member
Nov 13, 1999
2,145
505
164
Palm Beach Gardens, FL
That's what I was afraid of, I've seen most of them done that way but I wanted to try to do it without disturbing the big power wires. I'm going to try to wire the lights in a parallel circuit to the signal wire and see how it works.
Try it, but it could disrupt the relay unless you control the LED current, i.e. keep it low & the LED dim.
LED current compared to motor current - insignificant
LED current compared to relay coil current - significant