question for '82 owners on A/C low speed fan

[john walker's workshop]

i swear these things have a low speed a/c fan function. low medium and high. the wiring diagram shows a completed circuit for the red wire w/green trace from the console fan switch, straight through to the resistor below the passenger footboard, and on to the evaporator fan in the smuggler's box via the red/white wire. well, on this car, the red w/green trace wire ends at a pin on the resistor that doesn't connect to anything. i pulled a resistor out of my '82 parts car and it was the same. just a pin mounted in the bakelite body of the resistor. wooooooo....twilight zone. does your 82 have a low speed? that would be the first click on the fan switch that also activates the compressor clutch.

[OSI930]

My '80 SC does.

[walt]

Yes for my 82.

[john walker's workshop]

then the question is, how does that red w/green trace wire manage to get it's power through the resistor and to the motor when it dead ends at the resistor. i'll figure it out eventually, but it escapes me at this moment. i can get the low speed by jumping the resistor dead end terminal to the terminal right next to it. dum dum dum dum dum dum.

[1982911SCTarga]

Ditto on the three speeds for my '82. My A/C even works, too.

That resistor set-up is something out of Lionel Trains meets Behr Group.

Brian

[Mysterytrain]

So you are saying that the Red/Green wire is connected at terminal 3 on the drawing below. Is it the green or the blue connections don't exist?? Hmmm, are Low and Medium jumpered at the switch..maybe the factory decided the low speed was useless?

[john walker's workshop]

yes, on the two resistor units i checked, terminal 3 dead ends right at the resistor. the wiring diagrams don't show that. medium and high work fine. i need to check it on a car that actually does have the low speed working and see if the resistor unit is different on those cars. funny thing is, the owner swears it used to work.

[rs6er]

I have an '81 and although my car doesn't cool any more, I do get 3 speeds on the fan. How can I help?

[rs6er]

I have an '81 and although my car doesn't cool any more, I do get 3 speeds on the fan. How can I help?

[john walker's workshop]

first test, if it has 3 speeds, is to check with a test light on the red w/white trace wire at the resistor plug to see if it gets power on low speed. that wire goes to the fan, from the resistor. the resistor is under the passenger foot board. i just checked the resistor on a '83 and it has the same dead end terminal, but none of the fan speeds work on that one anyway.

[rs6er]

Originally posted by john walker's workshop
first test, if it has 3 speeds, is to check with a test light on the red w/white trace wire at the resistor plug to see if it gets power on low speed. that wire goes to the fan, from the resistor. the resistor is under the passenger foot board. i just checked the resistor on a '83 and it has the same dead end terminal, but none of the fan speeds work on that one anyway.

I'm confused. I pulled the floorboard. Do you mean the red/wire in the 4-prong plug that plugs into the firewall? Probably not because the fan works even if the plug isn't plugged in. Is the resistor somewhere else?

[edgemar]

When I turn the fan on the compressor always engages even at the lowest speed.

[rs6er]

This is with everything turned counter-clockwise/

[john walker's workshop]

i got this image from a previous post. the red/white wire in the plug goes to the evap fan. should get power out of the resistor on any fan speed.

the fan works still, with it unplugged??? haven't tried that.

the isolated terminal is seen below the top spring, to the left. the red/green wire for low speed goes there. why?

[rs6er]

Here's what mine looks like

[john walker's workshop]

that's the plug side. that red/green wire gets power from the first click of the fan switch, and according to the diagram, goes through the resistor, comes out in the red/white wire and on to the fan. so does the red/white wire show power on the low fan speed? mine doesn't. plugged in of course.

[1982911SCTarga]

I hope you get this figured out, John. I just went out to re-check mine and I've got three speeds. Bear in mind that the lowest setting doesn't move a tremendous amount of air. Also, as noted earlier, on blower setting one, you should hear the A/C clutch engage.

Is it possible that the evaporator wiring is jake, but the evaporator blower motor is on its way out and just isn't getting enough juice to get going?

Before I R&R'd my A/C, my evaporator blower didn't blow all that great until I took the unit apart and cleaned and oiled the motor bearings.

By the way, are all three fan speeds checked in a concours competition?

Brian

[bazar01]

that's the plug side. that red/green wire gets power from the first click of the fan switch, and according to the diagram, goes through the resistor, comes out in the red/white wire and on to the fan. so does the red/white wire show power on the low fan speed? mine doesn't. plugged in of course.

The way it looks, red/green wire from slow speed position switch goes to the isolated terminal that is supposed to be connected to the top resistor. Then goes to the lower resistor for maximum voltage drop then to red/white wire to the fan. It looks like the isolated terminal has lost its connection to the top resistor.

Medium speed goes straight to the lower resistor only and high speed bypasses both resistors.

Hope that helps.

[john walker's workshop]

on 3 resistors that i have checked, they all have the isolated terminal. that's why i'm stumped as to how the low speed could ever work.

[kuehl]

There where two styles of the Behr evaporator box style resistor pack for the evaporator fan speed control. Both function the same. All the years up through 1989 (non 964) have three speeds "nothing", "nothing" and full blast. The resistance is stamped alongside the resistor coil. Think of the resistors alike shunts.
If you are not getting fan speed "1" (first CW position) look at Mystery Trains schematic and check for power at "L(3)" otherwise consider a new motor or a temp squirt as suggested by 1982911SCTarga; and then a new motor in time (sooner or later depending upon what is left)