[LPete]

Originally Posted by Pepi

So unless the fan speed switch is selected on any other speed to overrride low, low is all you will get with selector switch on MAC A/C.

It looks to me like you would have low speed all the time with the ignition on and heater off, but when you turn the heater mode switch to any position but off, the blower will run on M1, M2 or high, depending on the fan switch setting. This mode switch is different, and doesn't need the extra wire from the Max/AC terminal to the high blower relay.

I think this will work, as long as the correct switch is used with this harness. The correct switch will be hot on pin 2 (pin 5 has continuity to pin 5) in all positions, including Max A/C. The '77 switch (if it matches the '77 diagram) won't be hot on pin 2 in Max A/C.

["QUICK-SILVER"]

You guys look back at the wiring diagrams (specifically Low coast/cabin vent) power feed. It's routed different to the blower between the two models in question. It should explain why wires aren't doing what you'ld want/expect. Note how 77 changes from low coast/cabin vent to high when the high speed blower is energized.

If you want it to work like factory you definitely need to use a single year complete harness (under dash and under hood), switches, and relays to straighten this thing out.

Look how "77" cabin vent goes through the resistor then the high speed blower relay (5 terminal) then to the blower motor. 75 used a jumper wire inside for cabin vent power.

Blower power did some back tracking in 75 like older model cars did. 77 was more of a straight shot.

Anyhow, complete matching harnesses along with correct components should put an end to this. Use which ever year you want, just use all the parts from that year.

Both systems pretty much do the same thing. How they did it (power routing) is what's different.

-

[vidguy]

I didnt get a chance to futz with this last night.
Quicksilver, thanks! I have abandonded the 75 parts entirely INSIDE that car.

I do have an engine arness from a later year, likely a 77 or 78 and the 5 terminal relay that matches it's connector. I will see how it compares to the 78 diagram Pepi uploaded.
The only reason I bought the 5 position relay was to try this. It was cheap...

I dont believe the actual Fan Switch on the post 76 controls are different amongst years?

At this point I have enough wiring to re-build the harness from parts! and I will if I have to!

[Pepi]

If any of those wiring diagrams aren't coming out well, if you pm me your email address, I can email you the pictures, hopefully better.

[vidguy]

Pepi- No they are fine. Thank you very much!

I just spent the morning recreating the 78 diagram out of the 2 later model (77 -78) harnesses I had. the 78 harness I have matched Pepi's 78 diagram exactly but had a missing heater power wire. (what is labeled as ORANGE, top left) I replaced that with a wire from the other..
I added the new resistor and the 5 position relay. And I used the controller harness that matches the Diagram (single Brown wire)
So as far as I can tell, except for the AC Side...AC Pressure Switch, Compressor Clutch and Thermal Switch..... I have it all as it should be. All 78 stuff..


As best as I can tell all of the wires are correct except the GREEN wire going to the compressor pressure switch in the diagram. My Compressor in the 75 was different and didnt have that compressor pressure switch, so I didnt try to change any of that.

As if right now I have the AC side of the harness unplugged.. everything off of the GREEN wire is disconnected. I also had to leave my 75 Temperature Switch disconnected as the connector is different on the 78 harness.

I made sure the Controller Harness under the dash had the BLUE and ORANGE wires in the original positions. I have traced all of the wires and they all look correct.

Now everything works as it should EXCEPT... I have NO HIGH at anytime. I get LOW always, I get the 2 medium positions correctly. But If I slide the Lever to MAX A/C, or, If I put the switch to HI at any Lever position, the brown wire coming out of the Control switch gets hot and the HI fan doesn't blow. I once again jumped the RED and what would be the ORANGE wire to the blower at the relay and the HI speed works.
It appears that I am STILL not getting power to the Orange Wire on the Fan Switch.

Here is the relay wiring. I cant tell from the diagram which wire should go where but this is how both of my 77 78 harnesses are/were.

On my Relay the terminals are numbered:
1= Power to the Heater (BLACK-ORANGE) in my case (replaced that wire.
2= RED to Alternator stud
3= Black to Heater Ground. In the diagram it is a "T" that also goes to the AC side which I dont have hooked up right now. I added a connector and connected it to my Blower ground. For now I grounded the other end to the Firewall ground.
4= Grey wire From the Controller harness connector
5= Blue - Goes to Resistor.


I even took apart one of the Rotary switches to see if the contacts were bad. I dont believe they are... and those things are a little tricky to R&R......3 little springs I wasnt expecting... Again I tried both controllers, (hence both fan switches) and both of my controller harnesses - the 77 and 78 (with the BLUE ORANGE wires in the original positions.)

I did not try the swapped BLUE ORANGE on the controller harness, with this new engine harness arrangement.

Im not sure what's next with this.. I even tried this arrangement with my 4 terminal relay but no go.

[LPete]

Disconnect the connector at the fan switch, and jump the orange and brown wires (with the mode selector turned on). The blower should turn on high. Do this, then report back. (Make sure the brown wire is hot before you jump them).

[Pepi]

Originally Posted by vidguy

It appears that I am STILL not getting power to the Orange Wire on the Fan Switch.

Here is the relay wiring. I cant tell from the diagram which wire should go where but this is how both of my 77 78 harnesses are/were.

On my Relay the terminals are numbered:
1= Power to the Heater (BLACK-ORANGE) in my case (replaced that wire.
2= RED to Alternator stud
3= Black to Heater Ground. In the diagram it is a "T" that also goes to the AC side which I dont have hooked up right now. I added a connector and connected it to my Blower ground. For now I grounded the other end to the Firewall ground.
4= Grey wire From the Controller harness connector
5= Blue - Goes to Resistor.


I even took apart one of the Rotary switches to see if the contacts were bad. I dont believe they are... and those things are a little tricky to R&R......3 little springs I wasnt expecting... Again I tried both controllers, (hence both fan switches) and both of my controller harnesses - the 77 and 78 (with the BLUE ORANGE wires in the original positions.)

I did not try the swapped BLUE ORANGE on the controller harness, with this new engine harness arrangement.

It appears as though the 5 terminal relay is wired up correctly, I was just tracing it all out on the diagram, and looks good. Have you checked continuity on the switch from where the brown wire hooks up to and where the orange wire hooks up to on high?

That is where I would start, make sure you have continuity through switch, and the you could even back probe it to see if you are getting 12V out of the switch. If you are and that is good, make sure you are getting power at the next connector then to make sure you don't have a bad orange wire. The gray/black wire should be matching up with the orange wire after that connector. Again, if you have power that far, then at the gray/black wire at relay.

Strange that you had HI working a few days ago though.

It sounds good for everything else working at different speeds.

[vidguy]

Lee- Pepi-
I went out - I am NOT getting FAN when jumping the BROWN and ORANGE at the Fan Switch connector.. With MODE lever in an ON position. Brown is energized.

I then tried to jump the GREY and RED at the Relay with the RELAY plugged into the connector... I get sparks but no fan, no click of the relay...
Does it seem like the Relay isnt getting energized and clicking? The SWITCH may be sending current through the ORANGE wire then to the GREY wire but the relay isnt clicking...Its new, but... I guess Ill try another.
Yes Darn it, I had HI THE other day but, HI at ALL MODE positions, even OFF..

I will try it tomorrow on the second fan switch I have to be sure.. But it seems like the Relay isnt operating as it should.

Also to be clear, in my previous post I said that "the BROWN wire coming off the switch gets HOT in HI but the fan doesnt blow" I meant it HEATS up in the HI position.
Thank you very Much.

[LPete]

Unplug the relay, and hook power and ground to the two small-wire terminals of the relay (gray and black). The relay should click. If it doesn't, try reversing your connections. If it doesn't click with either setup it's bad. The reason for reversing the connections is that there could be a diode in parallel with the coil (although the wiring diagram doesn't show one).

[Pepi]

I don't think it should matter looking at the wiring diagram, but stranger things have been known to do stuff...Is the relay hooded up to the firewall during this? Sometimes the relay case needs to be grounded.

Like I said, should'nt because you have a ground wire (black), but doesn't hurt to try.

[vidguy]

Bottom line here after testing it again this evening: I DO NOT GET POWER TO THE FAN SWITCH on the BROWN / WHITE WIRE from the Rotary Switch IN MAX AC.. GRRRRR....
I'ts not the Relay, Its not the Grey Wire... Its not the Fan Switch.

This is using the 78 harness inside with the 2 YELLOW WIRES and the 78 harness in the engine compartment. (not that that matters for this particular issue) The two yellow wires are what allow the LOW speed to work at all times.


I figured out how to get the wires/terminals out of the Rotary Switch connector and was going to try slipping it into the other Rotary Switch terminal that is ALWAYS HOT.

Here are some random thoughts..
I wonder if my controllers are not A/C controllers. Even though they have the detents for it.
I wonder if there is a different Rotary Switch for Non A/C and A/C..
Does the A/C GREEN wire power the Fan on MAX A/C Somehow?

Lee, in Post 81, what switch are you referring to here?
I think this will work, as long as the correct switch is used with this harness. The correct switch will be hot on pin 2 (pin 5 has continuity to pin 5) in all positions, including Max A/C. The '77 switch (if it matches the '77 diagram) won't be hot on pin 2 in Max A/C.
The rotary switch, correct? At this point, my wiring looks just like the 78 Diagram Pepi posted,
Thanks fellas....

[LPete]

I don't have time to go back and look right now, but remember how the '77 diagram showed the switch being different than the '78? The '77 switch (if the drawing is accurate) turns the high blower on in Max A/C, while the '78 switch doesn't -- the fan switch controls the blower speed, even in Max A/C. The wiring has to match the switch.

[Pepi]

Originally Posted by vidguy

Bottom line here after testing it again this evening: I DO NOT GET POWER TO THE FAN SWITCH on the BROWN / WHITE WIRE from the Rotary Switch IN MAX AC.. GRRRRR....
I'ts not the Relay, Its not the Grey Wire... Its not the Fan Switch.

I forget, where is the brown/white wire coming from? Is this the harness with the two brown white wires, or the one with two yellow wires?

[vidguy]

Pepi-
This is using the Rotary Switch Connector with a yellow wire coming out of the same connector on the Rotary Switch that has the the short YELLOW WIRE that gets power from Fuse Block BROWN POWER feed
And a single BROWN wire.
That YELLOW wire goes to the Harness connector
BROWN goes to the Fan Switch.
It appears to be as the 78 diagram says it should be.
At this point I am using the harness / connector on the LEFT in the photo attached. I believe it is the 78 setup. This matches the Engine side of the harness I am using which I believe is correct to the 78 Diagram. I'm trying to be ALL 78 right now :-)

Thanks,

[LPete]

Test continuity on the mode switch between pins 2 and 5 in both A/C and Max A/C, then test continuity between pins 1 and 5, again in A/C and Max A/C. We need to figure out if the switches match the '77 or the '78 diagram.

Did you ever try running the high blower relay from the fan switch?

[vidguy]

Did you ever try running the high blower relay from the fan switch?

Lee, how would I do that?
I will test continuity this morning, I have the Meter in the car I think. I did test the Rotary Switch terminals last night, but I dont recall the numbers on the switch. I couldnt be sure which was which on the Diagram.
I do know that in MAX AC, the BROWN TERMINAL on the Rotary Switch is NOT Energized. The Terminal with the GREEN AC wire IS.

[LPete]

Like this:

Originally Posted by LPete

Disconnect the connector at the fan switch, and jump the orange and brown wires (with the mode selector turned on). The blower should turn on high. Do this, then report back. (Make sure the brown wire is hot before you jump them).

[LPete]

Look carefully at the mode switches in the two diagrams -- the Max A/C connections inside the switch are different. On the '77, on Max A/C the blower power comes out pin 1, and energizes the high blower relay. The fan switch does nothing. On the '78, the fan switch works the same in Max A/C as it does in any other position.

My guess is you have '77 switches. We have to find out, thus the continuity tests. :-)

[Pepi]

If you jumper the yellow and brown wire, see if everything works then. That should allow you to control the fan speed in all four positions.

Like Lee said, we need to find out what style switch you have, It is very hard to tell on the diagram, but I think Lee is right where as the 78 doesn't put the fan on high automatically with MAX A/C.

Continuity test will show.

[vidguy]

Pepi-
Here I am testing continuity in MAX AC. The left connection is the POWER and the other is the BROWN wire.
There is no continuity.
Compared to the AC GREEN wire in the same mode position.
Ill go out and jump the POWER and the BROWN and see what happens!
---------------

OK. I don't know what you are going to think. but.. . no HI fan jumping the YELLOW and BROWN..

I took the connector off of the Rotary Switch and tried jumping Yellow and Brown and I can get all the speeds except HI. HI just sparks...

I tried it with the connector plugged onto the Rotary Switch. in MODE MAX AC, I opened the connector and Jumped YELLOW and BROWN and, again, I can get the OTHER Speeds so that's good, but no HI...

Since moving to the all 78 wiring with the 5 terminal relay I havent gotten HI to work.
Last time we did was when I had the wires swapped (Orange / Blue)

Thanks a LOT guys..
Ill try a few more things..

I think I may buy another 77 later controller just to see if all 3 are the same....