HVAC doesn't work

[BYT86GN]

My A/C has been acting up lately. At first my blower would not run in the high position. I ended up changing out the switch for the fan speed and I also changed out the compressor relay. That temporarily fixed the problem. Now my A/C doesn't work at all. I checked the resistor and it appears to be fine. I found this connector that I think might be the problem. As you can see the 12v fusible link from the starter is badly corroded. When I pulled the connector apart I noticed that the ground was not hooked up to anything. It looked like it was making contact with the power supply. Does any one know where the ground is supposed to connect to. Any help would be greatly appreciated. Thanks
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Sorry for the big pictures.

[Ts86ttype]

I have checked the electrical manual and my car... That ground comes to one side of the connector and there is nothing on the other side... A lot of time a wiring harness is put together for more than one application and or engine combo... If that connector was not making good contact the heat just melted the plastic and then made contact with the ground... I would have thought that would have blown the fusible link... Either way that ground wire does go back into the wiring harness and splices into a ground wire that is G130... G130 is located inside the car near the radio... More important the RED wire and the Blue wire in that connector have to be hooked up to make the the system work... The Red is a power source and the Blue goes to the pressure cycling switch, which in turn will supply power to the A/C clutch... Tom G.

[BYT86GN]

Man that is awesome information. Thanks alot Tom I really appreciate it. I am still trouble shooting. What book are you using and where can I buy one. Thanks Mike

[Ts86ttype]

Mike, the info is out of the section 8A of the 86 Buick service manual... You can find some on E-Bay at times... Tom G.

[BYT86GN]

Hey guys just to give you an update this problem has got me baffled. I still can't get my a/c to work. The blower will not run in any position even if I put the selector switch in vent. I put battery voltage on the blower to make sure it will run and it does. I checked the voltages at the resistor and don't get anything but when I disconnect the blower relay I get voltage in all fan positions. I replaced the blower relay and still can can't the a/c to work. So far I have put in a new resistor, blower relay, compressor relay, and dash control head. I also tried grounding out the a/c cut out switch and still can't get my a/c to work. Does anyone have any advice or has anyone else had this problem. Oh yah I checked the fuse as well and it's still good.

[Ts86ttype]

Mike, does your car have a manual or electronic control head??? Want to make sure we are on the same page in the electronic manual... Tom G.

[BYT86GN]

Hey Tom my a/c is a manual control head .

[Ts86ttype]

Mike, With the relay disconnected you will have power on all the resistor wires... What I would like you to do is plug everything back in BUT the PURPLE wire at the blower motor... Turn on your ignition and put your test light into the connector at the at the purple wire... It should light and I think it will... I think you have a bad blower motor and the only way it may run is with direct battery voltage... The lower voltage that comes out of the resistor block will not make it work... Maybe bad brushes or bad bushings in the blower motor are causing you the problem ... Give it a try and let us know what happens... Tom G.

[BYT86GN]

Hey Tom sorry for the late reply, I have been busy at work so I haven't had a chance to tinker with it. I tried what you said today but I didn't have a test light so I used a fluke meter. When I connected everything back to normal and unplugged the purple wire to the blower I tested it and only got 6 volts on the purple wire.:confused: I checked the red wire going into the relay from the starter and I am getting 12 volts from there. I checked the brown wire going into the resistor and I am only getting 6 volts there as well. I checked to make sure the fuse wasn't blown and it was good. What I also noticed was that when the car is running and I try to turn on the a/c the compressor clutch does not engage either. I tried the paper clip trick in the cut-out switch to see if it would cause the clutch to engage and nothing is happening. :dunno: I might just fork over the money and let one of the electric shops deal with it. I will keep you guys informed if I find something out. Thanks for all you help

[Ts86ttype]

Mike, Don't give up yet... I will bring home my fluke meter and get the voltages at the different terminals and get back to you... You can fix this... Tom G.

[Ts86ttype]

Mike, here goes...
A/C control head on Max or anything but off, fan switch in lowest position...

Brown wire at resistor block 12 volts.
Dark blue wire out 3 volts.
Purple wire at blower motor, plugged in, 3 volts... Motor should be running very slowly... Make sure it has a good ground... All the steps, purple wire plugged in.

Fan switch in medium 1, one step up from low...
Tan wire at resistor block 10 volts.
Dark blue out 6.0 volts.
Purple wire at blower 6.0 volts.

Fan switch in medium 2, two steps up from lowest.
Light blue wire 9.0 to 10.0 volts.
Dark blue out 8.0 volts.
Purple wire at blower 8.0 volts.

High blow.
Orange wire at the high blow relay 12.0 volts. That turns on the relay and the big red wire at the relay has 12.0 volts, that then goes out the purple wire to your blower motor and there is 12.0 volts there and the blower is going full bore...
Let us know what you find and then we can go after the A/C control... Tom G.

[BYT86GN]

Tom I will give it another shot tomorrow. I believe I have done this check before based on the cd that I bought from you. Thanks for your time and help. Eventually I will figure this out and if not I'm just gonna fork over the money an have an electrician deal with it.

[BYT86GN]

Tom here is what I did. I disconnected every thing from the dash head control all the way back to the relay. First I tested the connector behind the glove box. I put the key in run changed the selector to vent and I checked voltage at the brown wire spade. I got 12v there, then I moved the selector to the med low position and checked the light tan wire spade. I was still showing 12v there and 12v on the brown wire spade. I went to the next position med hi and checked the light blue wire spade and, I got 12v there as well as on the brown wire spade. I checked the hi positon and got 12v on the orange wire. I then reconnected the wire plugs behind the glove box and proceeded to the resistor terminals. I am getting 12v on all of them with the relay disconnected and the blower disconnected. I then connected the relay and I am getting 12v on the resistor wires and at the relay red, blue and purple wires. I got 12v on the orange wire at the relay when I moved the selector to Hi. Next I turned the key to the off position and reconnected the purple wire to the blower. I turned the key back to the on position and rechecked all the voltages. I am getting 6v on all wires except from the fusible link on the starter. In all positions the motor will not run. I disconnected the purple wire from the blower again and checked all voltages but nothing changed still showing 6v. I am gonna buy another blower motor and see if it will solve the problem. This is buggin the hell out of me cause the weather sucks down here.

[BYT86GN]

Well guys I tried changing out the blower motor and I am still unable to get my blower to run and my a/c to turn on. I finally decided to take it to the dealorship and the technicians are puzzled as well. They basically spent the whole day checking everything I have done and they are unable to determine the problem. I will take the gn back to them next friday for some more ball scratchin.

[Ts86ttype]

Mike, When this first started you found that bad connector with the red and blue wire in it, did you cut the bad connector out and hard wire the two wires or just cleaned it up and put it back together??? The reason I ask is that you seem to be loosing voltage and currant flow... Currant flow is a big deal here... Blower motors take a great deal of currant to run...That is why in HIGH BLOW you use a relay to get full currant flow to the motor... Let me know... Tom G.

[BYT86GN]

Tom when I found that corroded connector I went ahead and cut the connectors off and I used a coupling connector to put it back together. When I took my car to the dealorship they told me the blower was bad even though it was brand new. I am supposed to take it back to dealorship this friday. They are going to do some more testing. I will keep you informed when I find out something.

[BYT86GN]

Well I wanted to give you guys an update. I got my car back from the dealorship and after 257$ they finally found out what was wrong with my car. Or so they say. They tried to tell me that they replaced my blower switch and compressor relay. I wanted to speak to the mechanic that did the work on my car but unfortunately he was out test driving other cars. When I drove my car home I did some digging around to see what was all done. Come to find out that all they did was jumper the brown wire going to the resistor to the brown wire for the trunk release. They also did not replace any of the relays and switches they claim.

[Ts86ttype]

Mike, The brown wire to the trunk release is also fed from the A/C 25 amp fuse... Sounds like you were loosing currant flow from the fan switch to the resistor block and the easy way was to put in a good power source, the brown wire from your trunk release... The one place I see that you could loose currant would be at the connector that is right behind the glove box... It has the wires from your A/C control head... It is a 6 cavity connector, but I believe only 5 are being used... Check it out and see if it has a burnt wire or connector in the brown wire position... If that is were they but the jumper that that might be a place to fix... I would still ask the dealer and mechanic what is going on... Just my :2c: Tom G.

[BYT86GN]

Mike, The brown wire to the trunk release is also fed from the A/C 25 amp fuse... Sounds like you were loosing currant flow from the fan switch to the resistor block and the easy way was to put in a good power source, the brown wire from your trunk release... The one place I see that you could loose currant would be at the connector that is right behind the glove box... It has the wires from your A/C control head... It is a 6 cavity connector, but I believe only 5 are being used... Check it out and see if it has a burnt wire or connector in the brown wire position... If that is were they but the jumper that that might be a place to fix... I would still ask the dealer and mechanic what is going on... Just my :2c: Tom G.

Sorry for the late reply Tom. I have been busy been busy at work and my daughters Tee-ball. What you said is correct. I suspected that the brown wire was bad which is what I intially told the dealorship mechanics. Instead of getting a new harness they opted to just jumper the wires. When I get a chance I will take some photos of their fancy work. I did argue with them about the price justification since all they did was put on a temporary band-aid. But you know how they work if you complain about the price they will just find another way to justify the fees. In their case the standard answer was that they charged me for a minimum of 4 hours labor. Which I thought was covered under their diagnostic fees. In all it was a lesson learned which I hope I will never have to repeat. Thanks for all your help