My 69 has A/C and the blower motor only works on the two highest settings.
I figure it is the resistor, can it be something else? How can I check all this out to make sure?

Thanks.

The resistor is the most likely cause, but it could also be the blower switch or the wiring in between.

High speed doesn't go thru the resistor so I'd look at the switch first.

High speed works. And the speed just under high. It's the lower two speeds that don't work. I have a new Factory Fit harness.

Can you remove the resistor and test it some how with an ohm meter to see if it's bad?

Does anyone know which wires to check at the resistor to test the switch?
I mean what color wires at the resisitor to check for different speeds?

If you remove the resistor assembly, you will immediately see if they are bad or not. If they look questionable, here are some approximate resistance values for each resistor:

Terminals 1-4: 1.1 ohms
Terminals 1-3: .9 ohm
Terminals 3-2: .4 ohm

This view is looking at the terminals of the resistor assembly
.........___ #4
.........___ #3
..#2 ___ ___ #1

If they look good, here are some voltage readings at the resistors to look for.
Fan switch Low: 12 volts at terminal 4
Fan switch Med1: 12 volts at terminal 1
Fan switch Med2: 12 volts at terminal 3

Larry

I did some checking this evening and my resistor looks like new. So I don't think it is the problem.

I didn't have a volt/ohm meter but I had a good test light and
I found that at the plug going to the resistor I had no power on any wires other than the speed just below high(whatever that speed is).
That is the only position that I had any power at the resistor. In that position I had power at the #2 terminal (light blue wire).

I also checked inside the car at the switch. At the lower speeds the only wire with power on it was the top dark brown power feed wire. It seems like the switch isn't working.

I thought about taking a jumper wire and jumping power to the proper wires to see if it would work that way but I didn't have time and didn't know what wires I would need to make hot for each speed.

Does it sound like a bad switch to you guys? Also where this is an AC car is there another switch that could be causing this? Like the switch mounted on the heater box under the dash?

It's starting to sound like the fan switch. It seems strange, though, you should also have power at the purple wire when the switch is in high and the relay is actuated. Also, the power wire going to the fan switch should be tan. That wire comes from the Low Blow switch that's mounted next to the fan switch. The Low Blow Switch's power wire is brown.

Anyway, here's what wires to jump at the switch to get power to the resistors.

Brown(tan) to yellow, low speed.
Brown(tan) to light green, medium 1 speed.
Brown(tan) to light blue, medium 2 speed.
Brown(tan) to orange, high speed.

If this still doesn't get the fan motor to turn, there is a break between the switch and resistors, unlikely though. I'm betting on the switch. You might try using WD-40 inside the switch to help it clean the contacts as a last resort.

BTW, the switch on the heater box is the Diverter Door Switch. It supplies power to the compressor.

Larry

Well I feel like an idiot. It's working perfect now. After reading your post that the power feed should be tan and not brown, I checked my wiring. I had plugged the wrong connector to my fan switch. I had connected the plug that goes to the switch at the bottom of the controls to the fan speed switch. I swapped them and it works fine. Both plugs are the same and will plug in at either spot.

I couldn't figure why the colors were different that the wires out at the resistor, now I know. Good news is it works great.

What is the other switch at the bottom of the AC control panel for?

Thanks for the help.

Hey! I never noticed that you could do that! They are definately the same connector. I will have to remember that.

The switch at the bottom is the Low Blow Switch. It's main function is to supply power back through the fan switch to run the fan motor on low speed if the fan switch is turned off and if the compressor is running. This allows enough air flow across the evaporator to prevent icing on the coils.

Larry

Thanks Larry. They are the same connector and I just replaced my harnesses with new Factory Fit harnesses. I never even gave it much thought I just plugged them in and they fit. I never even noticed the two were the same until your comment about the power wire color.

The main thing is we've got it going now. Maybe this will help someone else too sometime from making the same mistake.

Thanks again.

Glad we could get you going!

Larry