On a long trip I shut my 86 z off and when started moving again I realized there was no air coming in from the vents and the a/c wasnt doing its normal groan. I tried all four speed, heat and vent combos and came up with nothing.
So after reading a good ten other posts about the blower motor not starting up I began to dig in.
First thing I did was check the fuses. all ok
tried to ground motor directly to battery still a no go.
Then I pulled the purple wire and direct powered the motor from the battery and it worked fine but the a/c did not engage.
I checked voltage on the infamous red wire by the passenger and found 14 volts on both sides of the connector and also at the relay plug.
I then jumped the red wire power to the purple wire from the relay and the blower started right up and the a/c engaged... so I replaced the relay.
Still did not work.
Can anyone tell we what the orange wire does and if there should be any voltage on it? I believe this must tell the relay when to send juice from the red wire to the purple wire to run the blower. of course it disappears somewhere in the wireloom of dispair.

The cooling fan does turn on when a/c mode is selected so i'm a bit lost.
any help would be greatly appreciated, im in texas so its still hot during the day and cold at night so I am trying to get it right.

 

Great troubleshooting!!

Diagram here will help you:
http://www.austinthirdgen.org/mkport...C60_manual.jpg

The orange wire you are asking about is sure enough the relay control wire. There should be voltage on it when you move the lever from OFF to a heating or cooling setting and select the HI speed on the HVAC control panel.

If this wire does not have power (my guess it that it does not), you can simply pull the HVAC panel out (just a few screws) and check the connector on the back for any obvious damage. Then I would test the brown power supply wire for voltage. If no voltage, double-check the HTR A/C fuse and power in its slot.

Where in Texas are you? In our part, it's not hot anymore (the fall is here) so we're enjoying the cooler weather with the killer humidity from Mexiko.

Let us know what you find.
Lou

 

The orange wire should be hot when you have it in HIGH. It powers the relay coil. Since you said the compressor is not running, I'd look at the brown wires coming in from the fuse box. Looks like there is a connector inline there that could be the problem. I'm too old and the pic is too small for me to read the number, but the service manual will tell you where to find that connector numbers location. Perhaps lou could post a link to that page or tell us where it is.

 

It's not hot in Texas any more, ha ha ha ha ha ha. It is in houston. It's getting better though, we've had some nice days. Sorry to be redundant about the orange wire, you really know these harnesses well. I can find my way around the FSM schematics, but I just don't have allot of experience pulling the actual harness apart on these cars so I have trouble finding where stuff is sometimes even with 3d drawings. Now on my old truck, that's a whole other story. No book, no pics, but I know where everything is and what it does (or doesn't .

 

thanks I will do some further investigation hopefully tonight or tomorrow. I was actually on a round trip from Austin to Houston and back.. started acting up first night in Houston and the trip back was fairly miserable. Although I do spend some time up north in the summers as well, the humidity and window fog got to me after the 2nd hour...

 

so i checked voltage at the fuse and that was good on both sides. I also pulled the hvac switch out and checked the plug that goes into the fan speed selector **** and found no voltage on any of the prongs that connect to it. Is there another relay in the dash board some place?

 

I just changed the fan speed selector switch ( heat / ac switch ) because the old one did look a bit beat up. So far no real progress has been made.

 

The brown wire coming into the HVAC control panel is the only wire that carries power to it. And it comes straight from the HTR A/C fuse. If there's power on that brown wire at the fuse panel and not on the HVAC control panel, I say there's a break in the wire somewhere. There is surprisingly a connector C202 in the brown wire but I do not know where it even is under the dash. It is possible that it is disconnected.

I DID find the C202 after searching here. Good old TGO!
https://www.thirdgen.org/forums/post...640-post8.html
Check out the first attached picture.

Hope this helps.
Lou

 

thanks, i can look out there again tomorrow, this looks like it has potential !

 

lou i think i found the culprit it looks like it might be that c202 connector. Its actually almost behind the stereo so i couldnt see it. With the plug off the hvac slide control ( flat plug) the brown wire was registering 12v along with a light green wire. The blower switch has a brown/wht wire with no voltage. i am taking a heat brake and will try to see if i can get this squared away.

 

confirmed, the c202 connector was shot. I must say its a useless connector in my opinion. I replaced the blower switch also as it looked like it may be the next thing to go