There is a very large class of people that own 65/66 Mustangs that, as far as I can tell, anyway, have been, for the most part, ignored entirely. They don't really want that 100 pt. show car that is so nice and was soooo expensive that they're afraid to drive it, they also don't want to make their car capable of achieving warp factor three. They just want this car that they dearly love to be able to cruise around smoothly and reliably, without having it dump them out on the side of the road or have it start making weird noises or belching out big clouds of funky-smelling smoke. And I think, truth be told, that this is by far the largest class of Mustang owners. They take their car to some technician when what they actually need is a mechanic, and this, frequently, does not work out very well at all for the owner. They don't want to re-engineer the entire car, they just want someone to fix what broke. These are the people that I am trying help out with this blog. Some problems require a little bit of back and forth, as in, "Try this." "I tried that and it didn't change anything."
" Oh. well, you probably need to try that." " I tried that and it helped, but it still isn't quite right." "Now you need to try this...." If you go to http://www.allfordmustangs.com/ and then go to the classics forums, you will be able to do that with a pretty hefty gathering of some very knowledgeable people that also happen to be very friendly. None of that ridiculous one-upmanship, no flaming or abuse, none of that stuff. Just good, solid advice from people that know what they are talking about.

Monday, January 3, 2011

Mustang heater blower motor 1965 and 1966

Here is how the heater blower motor works on the 65/66 Mustangs. If you click on the diagrams, they will pop out so that you can see the entire diagram. I made them as big as I could so that they would be easier to see.

  If your car is an early 65, as in 64 1/2 with a generator, and has the center position off switch, the second drawing is how that is wired. Power comes from the fuse box to the switch, and, goes from the switch to the blower motor. If you look at the blower motor itself from under the hood, you will see three wires sticking out of it. One is red, one is orange, and the other is black. The black wire is the ground wire, and should be attached to the firewall. The other two bring power to the motor from the switch.

If your car has the off position on the switch all the way over to the driver's side, the first drawing is how your car is wired. This is a system that can be a little confusing until one realizes that it is wired backwards from the way most of the stuff in this car is wired. Most systems have power coming from the switch to the component. The heater blower motor has power coming from the component to the switch. Power comes from the fuse box and goes straight to the blower motor on the brown wire. It leaves the blower motor through the yellow wire, which plugs into the resistor on the front of the heater box. There will also be a three wire harness that plugs into the resistor which goes to the switch. You will notice that there is no ground wire in this system. The switch feeds power from one of the three wires coming into it, depending on which position the switch is in, straight into the metal of the dash. It is important that the switch be making good contact with the unpainted metal of the dash on the back side, or, the system won't work, so, if you decide to paint your dash, make sure that the switch housing is still making good contact when you reinstall it.

There was also a center position/off two speed blower available in the later 65 model cars, which, at a glance, appears to be like the 64 1/2 from inside the car. It does not have the resistor on the heater box. however, these worked like the three speed blowers. Power comes from the fuse box to the blower motor and then goes to switch, which grounds on the dash. The resistor is an integral part of the switch.


Gina E said...

Thank you so much!! I was pulling my hair out. My car has had so many strange repairs. It is an "early" '65, which explains why my heater box with no resistor. However, previous owner decided to repair heater, and so I have 3 speed heater, 3 speed switch, and no place to plug in the resistor wires. Can I make a hole in the heater box? The wiring supports the 3-speed setup.

Veronica said...

Hi, Gina. It will be a bit more complicated than merely attaching the resistor to your heater box and plugging in the connector from the switch. The two blower motors work in an entirely different way. What you will need to do attach the resistor and plug in the wiring from the switch,but then you will need to a couple of other things. If the blower motor that you have sticking through the firewall has two wires coming out of it,unplug them both, turn the ignition key on, and check the two wires that you just unplugged the blower motor from, the two that are part of the wiring of the car, for power with a volt meter. If one of them shows power and the other does not, plug them back in. The one that did not show power should be yellow. There will also be a yellow wire (the other end of the same wire) with a flat spade connector on the end of it. Plug that into the connector on the resistor that is a little bit away from the other three, and you should have a fully functional blower motor.

If both of the wires you unplugged the blower motor from are hot, plug one of them into the motor and run a new wire from the other wire on the blower motor into the car and plug that into the single connector on the resistor.

If the blower motor has three wires, one a ground wire attached to the body of the car, and the other two are hot, disconnect the ground and do what I described in the last paragraph with the new wire.

If the blower motor has three wires, one a ground and one of the other two is hot and the other is not, disconnect the ground, and plug the other two into the blower motor, find the yellow wire sneaking around near the heater box and plug that into the isolated connector on the resistor.

One of these should have your heater up and running. Let me know which set-up you actually have, along with what color the wires are before you actually plug everything up and try to turn the system on, just to be safe.