Heater and Defrost Motor Switch Wiring

How is the stock heater and defrost motor switch supposed to be wired? I have a yellow wire with an inline fuse running from the ignition to the switch. I also have an orange and a red wire which run from the switch to the fan.

My switch was manufactured by Cole-Hersee Co. in Boston (love the "U.S.A." stamped on it after "Boston"). Here are photos of it from all sides (the vertical orientation is the same for each photo). It has the number 3 stamped on the bottom of the photo taken from the top. I believe it should be a two speed switch, but no matter how I hook up the three wires, I can only get the fan to run when the toggle is in the middle position. I have no idea if this is the low speed or high speed. It stops running when the toggle is placed in either of the two "outer" positions. I read elsewhere on this forum that the orange wire was supposed to be for the low speed and the red wire for the high (but of course I cannot find that thread right now). Which line goes where on the terminals on the back of the switch? Should the wires be connected in some particular order from top to bottom (with the number 3 being at the bottom)?

 

Upon a closer look, the back of the switch would appear to be stamped as follows:

top contact - L (for low speed?)
middle contact - B (for battery?)
bottom contact - H (for high speed?)

Assuming that the orange wire is for low speed and the red is for high, that would seem to indicate that the orange wire should be connected to the top contact, the yellow wire to the middle contact and the red wire to the bottom contact.

Can anyone tell me if this is right or, if not, how this should be wired?

 

Howard,

Thanks for the reply. I'll check the terminals with a meter tomorrow to make sure both are working (I presume the meter would also tell me the output for each terminal?)

It never occurred to me to see if Cole Hersee was still in business. The correct version of this switch is actually on page 23 of section B of their master catalog (http://www.colehersee.com/assets/files/catalogs/1303152411-CLH-080MasterCatSectionB.pdf). It is part #551852 which is an On-On-Off switch. Here's the exact description:

551852 SP2C On-On-Off
Up: B-H, Center: B-L, Down: Off. Three screw terminals.
This universal switch can also be used to control heaters/
defrosters. Supplied without resistors.

And here's a website where you can buy one that includes photos - http://www.partdeal.com/cole-hersee-551852-bx.html?zmam=74973193&zmas=1&zmac=4&zmap=77152111&gclid=CNOq1fnKsbsCFYdFMgod4kEAUA. The back is stamped the same way as the one I pulled off of my jeep.

Can anyone still confirm for me which wire (the orange or the red) is supposed to be the low and the high speed? I think this will help me determine if my switch is bad and/or if my wiring is bad and/or if my motor is bad.

Thanks again for the reply, Howard. I wouldn't have found this without your help.

 

it will work weather the red (high) is on the top or bottom, it will just be wired backwards, meaning when you flip the switch to low you will get high. The red (high) goes on the bottom, and the orange (low) goes on top.

 

Just connect a hot wire to one of the wires from the blower motor and listen to the sound of the motor. Then connect the other wire and listen. You will be able tell which wire for which speed.
Note: Some motors require both wires to be hot at the same time for high speed. Other motors require the wires from the motor to be switched to ground to run.

 

You don't need to guess about this. Measure the switch to see if it connects one terminal to power for high speed, or both. It's just a switch - easy to characterize.

On second thought, I think it's unlikely that it matters which is high and which is low, since the wiring diagram makes no distinction between them. Just connect the red and orange to the remaining terminals and see if the switch behaves like you would expect.

 

there is only three connection, hot, high, low. I know some wire different but don't think this is one of them. Mine is wired High (red) on the bottom and low (orange) on the top, with a wire coming from the acc of ignition switch to the center post on heater switch.

 

Thanks, jeepcj. So your heater motor is off when the switch is oriented with the low terminal (orange wire) on the top and the high terminal on the bottom (red wire) and the toggle is pushed all the way down. When the toggle is in the middle your fan runs at the low speed and when the toggle is all the way up your fan runs at high speed. Do I have this right?

 

No, when the toggle is in the middle my fan is off, when I flip it up the fan runs on high, flip it down and it runs on low. When you flip the switch up, the other end of the switch go,s down making contact with the bottom wire (red, high), flip the switch down and the other end of the switch go,s up making contact with top wire (orange, low). So the high and low wires hook up opposite of how you flip the switch.

 

Thanks. Right now, my fan runs when the switch is in the middle. When I flip it up and jiggle it a little, the fan will run sometimes (at what sounds like the same motor speed as when the toggle is in the middle). When I flip it down, the fan won't run at all. Sounds like a faulty switch. I'll do some diagnostics when I get home tonight.

 

OK. Here's what I found. First, my switch seems to be set up properly. When the power source is connected to the input terminal (stamped with a B on the back) and the toggle is all the way down (which is the OFF position according to the heater control housing), neither output terminal (L or H) is live:



When the toggle is in the middle position, the upper (or L) terminal is live, and when the toggle is in the upper position, the lower (or H) terminal is live. But my fan runs at the same speed regardless of whether the orange or red wire is attached to the upper or lower terminal (or whether both are plugged into either terminal at the same time). I went ahead and connected the wires as suggested by others in this thread, orange to the upper (or low speed) terminal and red to the lower (or high speed) terminal:



Next, I traced the orange and red wires to the motor and here's what I found after removing some electrical tape applied by the PO:



The red and orange wires are connected to the same wire running to the motor. The other wire coming out of the motor is connected to a black wire that is grounded to the dash. The TSM shows three wires coming out of the stock motor, but my motor only has two:



So here are my questions:

1. Is this thing wired properly?
2. Is this a stock motor? or if it is an aftermarket motor, what kind is it?
3. According to the TSM (Heater and Defroster 13-3), "the blower switch has three positions: OFF, LOW and HIGH. It regulates the amount of current going into the blower motor with a fixed resistance, thereby regulating the speed of the blower fan speed." Given the fact that my fan runs at the same speed on either setting with either wire, does this mean my switch is faulty? For some reason, I thought the color of the wire had something to do with the fixed resistance.
4. Is there any way to know if the fan is running at high or low speed? If the switch is not providing fixed resistance like it should, does that mean that the amount of current flowing through the switch at either position is at maximum flow so to speak, so my fan is running on high in both positions? I hope not because it's not running very fast at its current speed.
5. How do I get my two speed fan?

 

On these older fan motors they normally have a wire connected to the outside housing running to ground. Then power to each wire running to the inside of the motor. I will tell you the red orange wires that are but connected together is not normal nor original. The 74 diagram that I have does not show me any wire colors so I will have to dig deeper.

 

Thanks, Walt. I just checked my motor again and did not find any evidence of a wire ever having been connected to the outside housing or any place where that connection might be made. Like yours, the 74 TSM wiring diagram I'm working from doesn't show colors for the wires nor does it reference them in the wiring diagram legend. Looking forward to learning what your deeper digging uncovers.

If I wanted to remove the motor, I presume I would start by removing the nuts from the two long bolts shown in the photos above (after of course disconnecting the red and orange wires at the switch). What would be next?

 

I believe the low speed could be controlled by a resistor in series with the low speed terminal of the switch. Not sure of the ohm value, that would be determined by the impedance of the motor. no need to remove the motor in my eyes. I would measure the motor resistance and get a hi wattage resistor about 25%-35% of that value. Should be a big ceramic one like a ballast resistor.

That quote from the manual sounds like it is calling for and external resistance.

 

Your switch is diff than mine. on mine the middle is off. I will actually go out and look at mine today and see how things are. Mine has only the red and orange wire coming from the motor as well.

 

Here is what I would do.

Normal things back up. The two wires coming from the motor are yellow and orange. Connect those back to the switch. Remove that wire that is grounded to the dash. Run a ground wire from that long stud on the motor to a known good ground and you should have both speeds.

 

Looking at his picture of the blower motor, it looks like it is stock. I say (looks) like. The diagram for 74-75 cj shows the two wires orange and yellow going to the switch with the motor case going to ground. If you clean off the wires at the motor and find they are in fact orange and yellow then I would think stock. If they are of a diff color then not stock. I then would follow Howards post. To answer your question about the two bolts holding the motor, those probably go all the way thru to the mounting housing. The squirrel cage fan would keep you from separating the motor from the housing.

 

the screws holding the sheet metal piece behind the blower motor come off and the whole thing(cage and motor) come out of the heater box.