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12v to grn/wht wire on fans

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Old 03-01-2020, 10:36 AM
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12v to grn/wht wire on fans

First it is an 89 LB9. Ok could someone lead me in the right direction of why i have 12v on my grn/wht wire to my secondary fan ( the fan that is controlled by AC switch & head switch on passenger side) I have 12 all the time for orange wire, 12v with key on for the brn wire then I get 12 volts to the green wire which should not have 12 volts should just be a ground. Where would the 12v be coming from?

Just fyi the fan that is controlled by the ECM (drivers side) works correctly.

I am open to any suggestions.
Old 03-01-2020, 02:04 PM
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Re: 12v to grn/wht wire on fans

That wire controls a battery-ended relay coil. Batt goes to one side of the coil; the other side goes to the grn/wht wire; the other end of the grn/wht wire goes to the fan switch; the sw is normally open (no connection through it) and when the fan sw reaches its set point temp, it closes (becomes a short from the pin to ground); that applies ground to the grn/wht wire, which completes the circuit through the coil, operating it. When the relay (electromagnetically operated switch) operates, it sends power to the fan motor. That means that with that connector unplugged from the relay, there should NEVER be any voltage of any kind on it.

Take a look at the other end, which should be located on the fan sw, pass side head between the #6 & #8 plugs. See if some PO has "improved" the circuit somehow. If so, remove all "improvements" and put it back like it was.
Old 03-01-2020, 02:10 PM
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Re: 12v to grn/wht wire on fans

^^^ what he said. Shouldn't be there.only ground or floating. Never 12V.
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