I'm connecting a new evaporation cooler to an existing 6 position wall dial using the existing wiring. The idiot owner who wired the original cooler put in 12/2 Romex, intead of 12/3 for the motor (the pump also has 12/2 Romex, and that is wired and working).

Coming out of the motor is a Red(Lo), Black(hi), White(Com) and Green(Ground).

Coming out of the switch is a black(hi), White(com) and green(Ground). The Red(lo) isn't connected.

I'm ok-ish with having the cooler only work on one setting (hi), so I wired the black to black, white to white, and ground to ground, and capped the Red.

Tried the switch, and the motor isn't turning on at any of the settings.

Do I have to run a new 12/3 Romex and connect the red, or, in theory, should this work? I'm not excited about fishing wires down from the roof if I can avoid it.

The other idea I had, is to combine the red (lo) and Black(hi) into one connector, and connect that to the black house wire, but I'm worried that tI'm going to overload the motor.

It's possible there is something else going on (it's an old house and old wiring). I just want to make sure this is likely not the problem before I start looking at other things, or pay to get an electrician in.

  • How was the old one hooked up? – longneck Jul 17 '17 at 17:36
  • @longneck Probably "wrong", since OP stated the last guy was an idiot. – Harper - Reinstate Monica Jul 17 '17 at 18:37
  • Wrong but still working is helpful to the diagnostic process. – longneck Jul 17 '17 at 18:52
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    Do you have any kind of schematic you could submit. It's real hard to answer a control question without any information. If you don't have a drawing then try and find the manufacturer's brand name, part number and any nameplate data. The more information you submit allows us to make a more informed answer. – Retired Master Electrician Jul 17 '17 at 18:53

First u can run a second 12/2 wire to get lo (red) Black is hi White neutral an green ground Wire accordingly

Ck utube video. Guy does a good job show n tell on hookup

Also ck switch with power off using an ohm metrr an see if u get the proper reads

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    Hello, and welcome to Stack Exchange. It's really hard to understand what you mean here; a little time editing your post could make it a much better answer. – Daniel Griscom Jun 15 '18 at 2:16
  • Not only is it hard to understand, it lacks links to the video suggested. Check utube [sic] video. WHICH YouTube video? There are millions. – The Evil Greebo Jun 15 '18 at 12:20

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