2.3 daily driver, fan won't come on??

Discussion in '2.3L (N/A & Turbo) Tech' started by Stangler, Apr 16, 2007.


  1. Jimmy2Times

    Jimmy2Times Member

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    Aright guys, I must be dumber than I thought when it comes to electrical systems... somebody help me out here. I wired up a manual switch for my fan but something isn't right. I keep blowing fuses (I've gone up to a 30 amp), so I tried briefly wiring the switch without a fuse. The fan barely came on that way and the wires going into the switch got hot after only a second. I unwired the switch immediately, but something is obviously wrong in my circuit.

    The manual switch has 2 connectors on it. I connect one to the 12V power source and one to the fan motor wire. The fan motor is grounded from the factory, so I didn't think I'd have to ground the switch. Is that wrong? If so, how do I ground the switch with only 2 connectors on it?

    I've tested the voltage coming from my ignition power source wire, and it's a good 12V+. I tested the resistance in the fan motor wire, and it's less than 1 ohm. So I don't think there's a problem with either of those wires. Do I just have the wrong kind of switch?
    #21
  2. ethangsmith

    ethangsmith New Member

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    Sounds like something isn't quite right there. I just wired mine up this morning for a manual switch. Just splice the yellow-with-red-stripe wire and install a switched ground coming off that. You can access that wire at the fan cotroller (under the dash to the left of the steering column). Then ground the circuit to the dash panel. Real easy and it will prevent the fan from staying on when you turn the car off because it will still be using the module. Plus, it's already fuse protected then.
    #22
  3. Jimmy2Times

    Jimmy2Times Member

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    I understand exactly what you're saying, but that won't work for me b/c I've eliminated the control unit (b/c it was fried). You're manual switch is just providing a resistance-free path to ground, which has the same effect as the temp switch opening to ground in the factory setup, but you're still relying on the relay in the control unit to provide power to the fan.

    I'm taking mine all the way back to the stoneage here. But thanks for the reply!
    #23
  4. mg man

    mg man Member

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    Now this is how I solved this on my 89 turbo Mustang. You can get a lower temp range one wire sensor from Vintage Air. A little pricey but available at lower temps. Also mine was burnt out where the fan pull current thu the board. I installed a relay outside the board. Ran the coil voltage to the coil connection on the board. Cut the 2 wires that the relay controls and hooked up to the n.o. connections on the relay. Now it kicks in at lower temp and ac controls it normally. Also don't have to remember to turn it on.
    #24
  5. ethangsmith

    ethangsmith New Member

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    Rereading your post, I would almost suspect yoour fan motor is bad. That would definitly cause high current draw. If it was pulling that much power (over 30amps) and barely moved, I'd say the motor is shot. If you can, substitue a known good one and see what that does.
    #25
  6. Jimmy2Times

    Jimmy2Times Member

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    Could a poor connection cause the fan motor to barely run and the wires to get hot? One of the car's previous owners apparently tried to fix the problem of the fan not turning on, and they performed some god-aweful splices on the wires going into the control module.

    I cleaned up the fan ground connection in the engine compartment, which was pretty cruddy, and I cut the bad splices out of the ignition power wire and fan motor wire under the dash. Now when I just jump those two wires with my single fuse holder with a 15-amp fuse in it, the fan comes on just fine and the wires don't get hot and the fuse doesn't blow. Could my problem have just been a bad ground or crappy splices or both?
    #26
  7. ethangsmith

    ethangsmith New Member

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    Very likely. Resistance causes heat. There may have been a short somewhere too. Monitor the system for a while though just to make sure the problem is corrected.
    #27
  8. Jimmy2Times

    Jimmy2Times Member

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    Yeah, I'll definitely keep my eye on it. I got a new switch to replace the questionable one I just had lying around. The new one has a ground lead in addition to power and load leads, and it lights up when it's flipped on so it was worth the $7 :)

    Initial tests indicate this setup is going to work. Thanks a lot for all the responses!
    #28
  9. 89' RICE COOKER

    89' RICE COOKER New Member

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    if your going back to the stone age, the easiest way is.... the two wires coming off the fan are a power and a ground. connect the power wire to a 12V sorce, preferably the ignition. take the ground wire off the fan and connect it to a manual switch with a 25amp fuse between. install the switch on the panel below the steering wheel and take a 5 inch wire offf the switch and ground it under the dash. it takes no more than 15 minutes to wire up and is about the easiest way you can make your fan work. if that doesnt work than you will need a new fan. if your sure your wiring is correct.
    #29
  10. Jimmy2Times

    Jimmy2Times Member

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    Thanks for all the input guys... looks like I finally got this one licked. I got a 3-pronged switch and hooked it up to the ignition power source, fan power, and ground wires going into the control module and mounted the switch next to the dimmer on the gauge cowl (it actually looks pretty slick and factory-like).

    All this time I was suspecting I was doing something wrong with my wiring, but I found that the culprit (besides a bad fan switch and burned out control module) was the factory harness connector for the fan power wire. It's a 3-wire connector under the starter solenoid, and somehow the prong for the fan power wire had gotten broken off inside the connector. It was barely making a connection, and sometimes power was getting to the fan and sometimes it wasn't.

    Now that I've fixed that, my manual switch seems to be working fine. :)
    #30
  11. pimpstang18

    pimpstang18 New Member

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    this was probably mentioned already but i didn't want to read 2 pages of posts on this... the fan won't kick on till it's about ready to overheat anyway, a quick fix is to wire it up through a fuse that gets hot when the ignition is turned on, i did this in mine and it runs much cooler, haven't had any problems yet and as an added bonus the a/c blows a lot colder because of the extra ait moving over the condenser
    #31
  12. rd

    rd Founding Member

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    I am late with this but I went through this on my 89.

    The module is called the IRCM, Integrated Relay Control Module. It has the relays for the fan and the EEC power relay.

    Mine was a 6 wire unit, some are 8. Later ones are mounted on the pass fender.

    What happens is that the fan is powered through the relay in the module, so full fan amps goe into it and out. The connectors have a history of melting if anything causes a high amp draw. That makes the connection worse.

    Ford and the aftermarket sell a pigtail repair kit for the wires. I melted the first one again. I changed the fan motor and the new one fried the wires again. So I put two 30 amp relays in parallel up front, and now just use the module to operate the relays, and its worked for two years. My replacement fan motor also seemed to pull way too many amps, like 50 or so. Then it died, and I put the stock one back in and it is working fine. Probably was fine to start.

    My fan comes on around 190 to 200, and anytime the ac is on.

    And it is still fully automatic.
    #32

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