Trouble with new circuit/relay

bikerjosh

Explorer
I have wired a bunch of new circuits through relays over the years for lights, horns, etc. I just ran a new circuit for an aux fan to cool a supplemental trans cooler and oil cooler at low speeds off road. I have tried numerous things to try and trouble shoot the circuit but still haven't determined the cause or issue.
Here is a rough drawing of the circuit and below is what I have tried, any thoughts or suggestions would be appreciated.

Picture is not great, hear is a brief explanation of path
. So I have a non-illuminated switch, ground wire runs to a known good ground under the dash w/several other accessories-Trigger wire runs through fire wall to a 30 amp relay connected to terminal 86. Terminal 30 on relay runs to a Blue Sea fuse box 15 amp fuse then to the battery. Terminal 85 on relay runs to known good ground in with two other circuits and engine ground strap. Terminal 87 runs to fan (80 watt-12 volt). Fan's other lead runs to a new ground on the frame (sanded clean)

What I've tried so far: attached 12volt source to positive lead at fan-result: fan spins- Assuming this means new ground is good.
Swapped out dash switches and relays to rule out those parts, no change.
Tested relays w/ power applied- both clicked and showed continuity between appropriate terminals.
Tested blue sea fuse box and relay terminal 30 to make sure both were getting power -both showed power
Ran a separate switch next to terminal 86 on relay, and ground it on battery, to rule out a short in the wire run from inside the truck to relay- no change
Replaced the checked(still good) but replaced fuse in blue sea fuse box-no change.

Any ideas? What didn't I check?
thanks :coffee:
 

MotoDave

Explorer
I may be missing something, but it looks like both 85 and 86 are both connected to ground?

Typically 85 is your ground for the relay, and 86 is a +12V switched trigger wire.

If you want to use 'switched ground' to control the relay, I believe 30 and 86 both get connected to constant +12V, and your switched ground 'trigger' lead goes to 85.
 

unseenone

Explorer
I ran into something like this before wiring remote relays. As it turned out, I needed to also power the switched circuit. I took a few pictures if that helps drop me a PM. I am not familiar with your particular relays.

You can troubleshoot this with a multi meter when manually switching the circuits as you described. I ended up wiring a jumper to power the circuit. I'll add a picture to this post if it helps.
 
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bikerjosh

Explorer
Term 86 on relay goes to a switch, the other tab on the switch goes to a ground (wow, did I "f" that up) does the other contact on the switch need to go to a separate power source? I thought the trigger wire going from the switch to the relay provided power? I should state I usually use illuminated switches that have three tabs one to the relay, one to the power source and one to the ground. Makes a little more sense now, I think; may have to blame this on the increased meds?

I may be missing something, but it looks like both 85 and 86 are both connected to ground?

Typically 85 is your ground for the relay, and 86 is a +12V switched trigger wire.

If you want to use 'switched ground' to control the relay, I believe 30 and 86 both get connected to constant +12V, and your switched ground 'trigger' lead goes to 85.
 

4x4junkie

Explorer
I may be missing something, but it looks like both 85 and 86 are both connected to ground?

Typically 85 is your ground for the relay, and 86 is a +12V switched trigger wire.

If you want to use 'switched ground' to control the relay, I believe 30 and 86 both get connected to constant +12V, and your switched ground 'trigger' lead goes to 85.
That is what I'm getting out of this also (both sides of the relay coil are going to ground).
(this assuming the issue is: "the fan does not turn on/relay doesn't click")

One of: pin 85 or 86, has to end up at a source of 12V power (polarity shouldn't matter). You could either move your wire coming from relay pin 85 over to a 12V power source (tying it together with pin 30 like mentioned should work), or, you can leave 85 grounded, and then move the wire to your switch to a 12V source. This should get the power flowing to the relay coil (energizing the relay) so your fan turns on.
 

bikerjosh

Explorer
Thanks Motodave. Works like a charm. Funny I never had a problem hooking up lit 3 prong switches. :sombrero: Now I know
 
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