IcemanG17

Well I have come full circle, from vacuum leaks with constant heat (no A/C) and no working HVAC flaps, to my choice of heat, ambient or A/C with most of the main flaps working!

My current problem was constant vacuum to the heatervalve (14in worth) no matter what the control head was set at? I found this link in Nichols:

http://www.nichols.nu/tip771.htm

It seemed like exactly what my car did, so I bought a used solenoid from 928intl for $25 and with the help of Bill Ball decided to give it a try. Removing the vacuum manifold is a real pain, since there is a screw right in the middle of the manifold right behind the stereo! Had to make a little tool to move the stereo foward to gain access to the center screw (coat hangers).

Sure enough the solenoid was bad & I left out the middle screw when we put it back together! Here are some pics of the progress!

SharkSkin

Good going, guys! You dodn't Keep Bill from finding his "clunk" though, did you?

IcemanG17

Dave
Actually quite the opposite....right after fixing my car...George & I rocked the car (good workout) from the side while Bill tracked down the clunk (you could hear it).....Bill did narrow it down to a couple possible items, but I'll let him tell that story!

SharkSkin

Good to hear there was progress! It seems everyone is doing a little of this n that in preparation for the fest. Did you ultimately reconnect the orange and blue lines?

Bill Ball

After we got Brian's heater back in working order, George dropped by and we poked and prodded underneath my car to try to diagnose a clunk in both the front and rear suspension. Found the front clunk by rocking the car hard - a bad swaybar link. The steering rack (original 150K) had some lateral play in the bushings but does not leak. Didn't quite know what to make of that. Could not reproduce the rear clunk, as it only happens on very hard turns. So, I spent a couple of more hours under the car checking every nut and bolt in the rear, did my rear brake pads WIWINT, but never found anything to account for the rear clunk. Heck.

Anyway, Brian and I each have one less problem.

SharkSkin

Bill,

Glad the front was simple. My rack with half the mileage has a bit of play too, no leaks. Did you double-check your battery hold-down, jack, etc?

Bill Ball

Dave:

Thanks for reminding me to check that area. It had occurred to me, but I haven't done that yet.

IcemanG17

Dave
Nope! Both the orange and blue leak like mad, so they will stay capped! Since I capped them everything else (& now the heater valve) work fine.... So I'm stuck with fresh air only (blue line recirc flap) & a non functioning center comb flap (I still don't really understand what that does anyway?) I still get very cold A/C so its I'm not in a big hurry to fix it!

On my longer term project list is to fix the recirc flap and comb flap & splice the lines back together!

Bill
A loose battery that moved just a bit under high G cornering? Do you have a smaller battery like an Optima? Possible, worth a check!

SharkSkin

I think the center comb mixes air to provide a certain temp at the vent. Not being able to engage recirc. just makes the AC work a bit harder, that's all.

the flyin' scotsman

Is there a test for the solenoids? I've assumed that they get input from the control head electrically and then open or close appropriately allowing vaccum to flow to the respective valves.

IcemanG17

Malcolm
The first test would be to make sure there are no vacuum leaks...after that you could pull the manifold and use a volt meter to test if the solenoid is getting voltage or not.

sharkmeister85

I've been scratching my head over a slightly different HVAC problem from any I've read about on this forum. I get heat blowing within a few minutes of start up, but after 15-20 minutes it goes away and I only get cold air, unless I switch to the defrost setting. Now I'm wondering if this might indicate that my same solenoid as the one you replaced is going bad. Any thoughts?
Glenn

the flyin' scotsman

Brian...............thanks for that but I've become quite the expert in removing the centre console and looking for vacuum leaks.

What I was really looking for is 2 fold:

1) are the solenoid on/off switches ie: they're either open or closed
2) although I have the full WSM what solenoids should be open/closed and differrent settings on the control head? those tables that are in the back of the air conditioning section are baffeling!!!

IcemanG17

Glenn
Thats an odd problem....its possible the solenoid is going bad, but the way I understand it they just straight fail...but its worth a check! The only other scenario I can think of is a bad control head...does anyone nearby have one you could swap out to test?

Malcolm
The solenoids are on/off switches..either they apply vacuum or don't

The diagrams are hard to read, I'm looking at 87-106 right now...to make it easier to understand I added some words/symbols to make it easier to understand...on the left (vertical) columm I added this

A= Recirculation flap
C= Defrost
D= Footwell
E= Center comb

For the top (horizontal) columm I added this:

Off= no change
middle= drew a square (for the center vent open)
Bottom= drew the down arrow
top/bottom= drew the up/down arrow
top= drew up arrow
Defrost= max defrost setting

it helped me understand the diagrams!

the flyin' scotsman

Thanks.............I did scribble on one of the pages but I'll print your note off and add it to the 'slightly full' section