Dual electric fans, FIRE!

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faster4231

faster4231

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I have jegs, dual electric fans, I am trying to run them completley manuel with a toggle switch on dash. I am having trouble with the relays and have had 2 electric fires so far!!. I want to go from battery to toggle back to relay , gound relay and have the out to the fans. Any idea's or even better a diagram? Everyone has suggested going from my ign from fuse box however that is complete for the fuel pump so I have no extra ACC from the fuse box. Cant I go straight from the starter and toggle somewhere alont the way? Please help. Car cant go without fans which means Im not going anywhere fast.
 
It doesn't take a lot of juice the open/close a relay. You could use just about any circuit in the car for that. The power supply that runs the fans is a separate circuit requiring much larger wire in and out of the relay. If I said, a relay is a remotely controled high current switch and the toggle switch is the remote for it, does that help?
 
faster4231 said:
I have jegs, dual electric fans, I am trying to run them completley manuel with a toggle switch on dash. I am having trouble with the relays and have had 2 electric fires so far!!. .
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You've either got something mis-wired, or the fans draw much more than the relays can handle.

We need specifics-----

what specific part no/ model fans? How much current do they draw?

what specific relays?

Are you sure you are wiring them off the relay contacts and not getting them in the switch circuit?

Can you describe specifically how it's wired?

And what specifically is burning up?
 
From battery to toggle? lol
 
I have two Jegs manufact fans. 12.5 amps apeice so I got two 30 amp relays.

I am trying to hook one fan up at the moment.

So, I ran a 12v constant line to the relay
grounded the relay. the ran another 12v source to the toggle back to the relay.

I have a inline fuse from the 12 to the relay.

I switch on and everything is fine for a min then the toggle smokes and the positive line from the switch melts all the way up

I like the idea of 12v straight to fan and the negitive to a toggle that seems sooo simple, do others advise this? If I get 5 yes's then I may go that way.
 
I also want or hear I can jump the 30 to 86 pin and put the toggle on that line, problem is I am not sure if this will also burn up. Can you imagine crusin flip on fans next thing you know your crouch is burning up on the hwy noooo thank you
 
Current flows through whatever it is connected to. Tto tie the toggle switch into the high current circuit defeats the purpose of installing a relay in the first place.
 
faster4231 said:
So, I ran a 12v constant line to the relay
grounded the relay. the ran another 12v source to the toggle back to the relay. .
Click to expand...

This tells us NOTHING. I finally surmised that you are using a "Bosch" relay judging from your terminal numbers, HERE is a Bosh relay layout:

relay1.jpg


So you should have (fuse holder/ fuse large enough for load, say, 20A for one fan) run to pin 86 and 30.

Run a single wire from 85 in to the switch, ground the other end of the switch

Hook your fan wire to relay terminal 87

DO NOT ground any relay terminals with this hookup
===========================================

ALTERNATELY run the fuse to30, hook the fan to 87

Ground 86, run 85 into the switch, and hook a 12V source to the other side of the switch. THIS ALSO should be fused.

The switch part of the circuit draws very little current. You can "rob" switch power off another circuit in the car.



=============================================

With either scheme, hook nothing to 87A

EDIT Geezus did I ever screw that up the first time around
 
Why not just build a basic relay and thermo switch? Hell I can build you one 20 minutes. I bet Slant Six Dan has a similar setup ready to ship.
You could even have the thermo switch activate by key ignition + that way even if the thermo was on the key would shut off the fans. Or you could leave it run till it cooled down the car by using the thermoswitch to ground method. Super simple.
 

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Sweet diagram lol. Does anyone have a lay out or can draw one, all I am trying to prevent is have an additional ACC source ran to the toggle, I dont have one in my set up available to be used all my other power sources are powering my elec fuel pump. Can I run two fused wires from starter, one going to 30 as a constant the other going to the toggle switch back to 86 or will this also burn out my toggle? 87 to fan and 85 ground
 
faster4231 said:
Sweet diagram lol. Does anyone have a lay out or can draw one, all I am trying to prevent is have an additional ACC source ran to the toggle, I dont have one in my set up available to be used all my other power sources are powering my elec fuel pump. Can I run two fused wires from starter, one going to 30 as a constant the other going to the toggle switch back to 86 or will this also burn out my toggle? 87 to fan and 85 ground
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That will work. When you say "starter" it's easier to use the big stud on the fender/ firewall mount starter relay

But the switch draws very little current. There is no need to poke another hot wire through the firewall just to feed the switch. YOU CAN ROB SWITCH POWER from another place inside the car. The "switch" part of the circuit draws far far less than 1 amp.
 
I mean draw the hot from the starter large bolt to get my 12v due to my battery being in trunk. Now I tried to rob power from my dash lights to power the switch however that blew out my dash lights. So I am thinking of going double hot to relay and use the toggle for ground I just found this online, Im a bit worried keeping it hot and relying on the switch to gound it but whats your thoughts, look at the link I posted
 
Here is a more basic diagram with slightly better 2nd grader quality drawing abilities.
 

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faster4231 said:
I mean draw the hot from the starter large bolt to get my 12v due to my battery being in trunk. Now I tried to rob power from my dash lights to power the switch however that blew out my dash lights. So I am thinking of going double hot to relay and use the toggle for ground I just found this online, Im a bit worried keeping it hot and relying on the switch to gound it but whats your thoughts, look at the link I posted
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I'm starting to get the idea that you are not reading what some of us are posting. I already told you how to hook it up, and it's exactly like your diagram, except the coil terminals are reversed.

WHY are you going down to the starter? Do you NOT have a starter relay?

On the dash lights-- worst possible choice. are you not aware that your dash lights go THROUGH THE DIMMER control on the headlight switch?

Personal choice, I don't like the idea of fans running / key off. I would pull power from, say, the radio plug. It has two wires, one is the dash light for the radio, the other is "switched" from the key.
 
Oh yea your diagram is the same w/0 fuses. Just take the hot from your starter relay bolt or where your battery cable meets the starter relay. If you want to simplify it more. Just ground the coil on the relay pole 85 and use an existing ig switched hot to activate the relay @ 86. The relay draws like .1 amps on the coil (speculated).
 
I am reading it , simple fact is that my car is not wired with a standard harness so it makes everything very different, if I was standard it would make it alot easier. So 67dart whats your thougts on that link. Using the toggle for simple ground and running hot to both posts on relay, does that seem reliable?
 
faster4231 said:
I am reading it , simple fact is that my car is not wired with a standard harness so it makes everything very different, if I was standard it would make it alot easier. So 67dart whats your thougts on that link. Using the toggle for simple ground and running hot to both posts on relay, does that seem reliable?
Click to expand...

Yeah, the only downside I have with that is:

A short in the wire from the relay to the toggle will cause the fans to stay on (and they're not through the key)

Feeding the coil circuit off the same great big fuse means that there is really no protection for that part of the circuit. If you are using a small toggle and no16/14 wire to the switch, a huge fuse needed to run the fan motors, will allow the small switching part of the circuit to "might melt."

So, not knowing how your car is wired, certainly makes guessing difficult.
 
Rice Nuker said:
We are all on the same page here I believe.

:)
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Pretty much, but you don't REALLY want to fuse one of those relays with 60A, do ya?


I agree, with a little more work, you can easily incorporate a thermal switch.
 
no i dont want to use a 60a fuse lol a 30 max. I am thinking I will spend the money to get the thermo switch, they arent that much I just hope that trying to wire them isnt this tough. Do most simply have a 12v hot and a ground? You dont have to do fancy relay with them as well do you?
 
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