fan switch?

Discussion in 'Fox 5.0 Mustang Tech' started by flashback87, May 31, 2011.

  1. i had a previous thread about smoke coming out of my dash and i found out it was my toggle switch power wire for my electric fan that fried.

    i was told to replace the wire and put a fuse holder in it for insurance. i did that and put a mini fuse holder in with a 5amp fuse. i blew that fuse. i then put a 20 amp fuse in and i blew that fuse. i then up graded the wiring to 14 guage and put another 20 amp fuse in and that one blew.

    i am really confused why i keep burning wires or blowing fuses. i have the toggle switched hooked straight up to the batter and grounded through the relay. i have the relay hooked up to the battery and grouned to the chasis. lastly i have the taurus fan power wire hooked up to the relay.

    i know i should get a controler and i plan on it but the mustang budget is getting out of hand so i need to chill on the spending a little:)

    please help me with this issue so i can get my car back on the road.

    your help is always greatly apreciated.
  2. Can you give us more details on how it is wired? A switch connected to the switch side of a relay should not be blowing fuses like that. It sounds like your toggle switch is wired into the power side of the relay or directly to the fan in which will blow fuses like that (and fry wires like you stated). Yes, a fan controller is the best bet, but a relay with the power side going from battery through the relay to the fan, and your toggle on the switch side of the relay should work fine.
  3. thanks for the reply. I have the power wire for my toggle switch only hooked up the battery. is is not going through the realy. is that the problem?

    if it is , does anyone have a diagram how it should be hooked up to the relay?

    my relay has 5 ports and i am only using 4.

    thanks again
  4. If you are good with electrical stuff (90% of the people here aren't), build your own controller. The numbers on the diagram (#86, #87, etc) refer to the numbers on the bottom of a typical automotive relay.


    Note that the temp sensor in the diagram needs to match the thermostat in your engine. The preferred arrangement is to have it open 5 degrees above the thermostat.

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  5. Do you have a digital multimeter? It's possible the relay is shorted out
  6. i do have a digital multi meter but i am still a little confused how to use it. how would i test the relay with the multi meter?

    also, if the relay was dead would the fan still come on becuase mine will come on untill the fuse blows?

    one more thing, so is the switch supposed to go through the relay or just straight to the battery?

    i know it is a lot of questions but i really apreciate the help:nice:
  7. Basically, the electricity needs to complete a loop. Power, to relay, to ground. The switch can go either on the power leg, or ground leg.

    The coil in the relay shouldn't draw more than an amp or way should it blow a 20a fuse.

    Can you eliminate the fan wiring and just complete the relay portion consisting of powering the coil?

    Just to are using 85 and 86 to power the relay coil?

    Eliminate the switch and just do a fuse, and short wiring, complete the look for the relay, if the fuse blows when you touch power to ground...the relay is shorted internally....get a new one
  8. right now i have 85 and 86 hooked up as grounds. one is grounding the relay and the other is grounding the toggle switch.

    is this wrong?
  9. That is not correct.

    85 and 86 is your coil for the relay. One side gets your fuses switched power, and the other side is grounded.

    30 and 87 are the switched contacts for the fan. 30 goes to battery (with a fuse) and 87 goes to fan power wire. Other fan wire is grounded.

    Post 4 shows it perfectly.

    What kind of switch os it? Is it lighted? Most switches have two connections. Power in and out...there is no ground. If it's a lighted switch, the ground is for the led...but doesn't connect to the relay.

    You can either install the relay or switch on the hot side (ahead of the relay and fan) or on the ground side (after relay or fan). Either way works. I like to install on HOt side to kill as much power as possible, but as shown above, the switch can be installed on ground leg side too.
  10. ok, im trying to understand this. my switch only has 2 conncections. one connection is going into 85 or 86(i forget which on) and the other conncetion is going to the battery. is this correct?

    then i have 85 or 86 hooked up to the chasis through a ground wire. is this correct?

    i think i have it how you stated but i just worded it wrong in my post above.

    also, i have the other 2 ports on the relay hooked up as you stated above. one going to the battery with the fuse and the other going to the power wire.
  11. i have noticed from your other posts in previous threats that you reference a hayden controler they sell at autozone for pretty cheap.

    is that pretty easy to install and do they still carry it? i checked their website and could not find it.

    would you happen to have a diagram showing instalation for the hayden controler?

  12. Just to be explicit, as the other guys have hooked it up........... :nice:

    85 and 86 can be small gauge wires with a small fuse. If you're using a small 30/40 relay, the polarity does not matter (it does with larger relays, which have a diode). Convention states that 85 goes to ground and 86 goes to power.

    So if 85 goes to ground and 86 goes to power, you should be ok. If your toggle switches ground, the output of the toggle will go to 85. 86 would have a small fuse and go to the battery (if you want to use the fan at all times) or accessory power (if you want the fan to only be on with the key being on).

    87 and 30 are the load carrying wires - they need to be 10 or numerically smaller (i.e. 10, 8........ AWG). 30 will get a large fuse (i.e. for some fans, 60 amps). 87 goes directly to the fan's + terminal, as the guys stated.

    The theory is that when 85 has ground and 86 has power, 30 and 87 connect, powering the fan.
  13. thanks for the reply. that is how i have it. 85 is going to the chasis for ground and 86 is going to the toggle switch connection. my toggle switch only has 2 connections and the other is going straight to the battery.

    so my toggle switch does not need to be grounded?

    im just trying to confirm where my 2 connections for the toggle switch should be going. 1 straight to the battery and the other to 86?

    thanks so much for helping me with this.
  14. That's correct. The switch simply interrupts power through the wire. Power come in 1 side, and goes out the other side when the switch is closed
  15. so it seems i have everything hooked up properly. so do you think the problem is the relay or could it be a bad switch?

    thanks for your patience and all the help
  16. I'm not sure what's going on with it at this point, but if your fan is not coming on when it should be, test the relay when the fan should be on and tell us what each prong is reading.
  17. my fan is coming on but it is blowing the fuse i have in the fuse holder for the toggle switch to the battery.
  18. Ok, take the fan wiring off the relay, just use the switch wiring,

    So, it should go battery, to fuse then to one post of switch. Then, from other post of switch, to 86.

    Then, put wire from 85 to ground.

    That's a simple switch leg. Turn it on, and listen for relay to click. If it does, and pops fuse, I bet the relay is shorted out.

    Can you post pics of any of yourmwiring or the relay.
  19. I'm running a setup similar to jrichker's diagram. It's nice to see the green LED on the dash when the fan's on. I also have the override switch just in case.
  20. dude you rock! thanks for putting it so simple:nice:

    i did what you said and un hooked the fan power wire from the relay. i flipped the toggle switch and the fuse did not blow. i then hooked the fan power wire back up to the relay and the fuse still did not blow. it might need to be running awhile for it to blow becuase on memorial day when i started the car the fan turned on but when i reached my destination the fan was off and fuse was blown.

    i think i attached a picture of the relay(1st time attaching something). i will try and explain the wiring as it is coming out of the relay.

    1. the wire at the top by my thumb is the going to a batter through a fuse holder

    2. the wire all the way to the left is going to the chasis for ground

    3. the wire on the bottom is going to the power wire for the fan

    4. the wire on the right is going to the toggle switch.

    5. the wire in the middle i am not using

    the relay came with those wires attached and i just ran my wires into them.

    thanks again

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