Hey all. Wasnt sure where to plop this. Hoping someone can help me out.

I havent put a ton of time into trying to figure it out on my own, but I figured Ide ask anyway.

On my 87, the wire/hose bundle for the HVAC had two vac hoses. One was a VAC supply line for the vents, the other told the heater control valve when to open/close.

On my 86, there is only one vac line. To supply the vents. There was NO heater control valve on the 86...

In the midst of swapping all the stuff from my 87 over to the 86, and Ide like to swap that HVAC bundle for two reasons. 1) the wires are already modified for the 4th gen A/C set up. and 2) I want to run a VAC controlled heater control valve again to keep my a/c temps down.

Any ideas on how or if this can be done? I looked real quick and didnt see anything obvious in the way of removing that bundle from either car. But I plan to look into again tonight. Not sure how to hook up that heater control valve VAC line inside the car.

Thanks as always folks!

J.

 

Ok...guess I should have just done it and not posted. I got it figured out and finished last night. Should...SHOULD work.

Just a quick run-down because I like all the threads I start to have a conclusion for people that stumble on them.

There is a slight diference between the 87 and the 86... Not sure if thats across the boards, or only with certain options or what.

First...the HVAC controls AND the vac lines are in fact a stand alone system. There is only one wire that comes from the chassis wiring...and Im not positive what it does. I didnt check. But the wiring can be pulled out as one piece.

Second...the controls are slightly different. The 87 had a special vac switch that operated the heater control valve when you move the temp. slider. This switch can be moved over to the 86 controls...there is a spot for it, but nothing there.

Also, the wiring is a tad different. The 86 used all of the wires on the selector switch. The 87 only had 3.

Here are a couple pictures just for the heck of it.

I had to move the entire wiring harness with the hard vac lines over to the 86. Then...I had to move the entire VAC hose harness over. Which was a pain at first, but then I got good at reaching the little diaphrams and it went quite smooth. So...the only thing thats left of the 86 system is the control panel.

The switch.


From the 86...no switch.


Here is the 86's vac harness. All individual lines that go out from there.


The 87's vac harness. Notice the supply split. The purple hose is what gets vac from the engine. The split supplies the vac switch with vac, and when the switch opens, it applies vac to the heater control valve.



This is what the purple hose hooks to on the 86.


And the 87...those are the hardlines that end up in the engine bay.


Here is what hooks to the hard lines on the 87...


And just the finished product. Wiring re-installed and hoses hooked up and routed.


I will also say, that brown plug has to be switched from the two units. Because of the way the brown wire hooks up. The plug is dfferent. I just took the pins out, and swapped the plug bodies.

Thats it!

J.

 

Do you have any more of these hvac harnesses? I've been trying to fix my vacuum leak for some time with 3 different control valves with no success and ended up cutting my harness to attach individually.