A/C Vacuum leak help request

[jrhende6]

Manual is a bit of a job...not immediately possible without some serious hackery. I'm reasonably sure that the entire upper half of the ducting assembly is different between them to accommodate the cable having to operate the blend door in the opposite direction. I think.

If you want to seasonally set it to full cold, you could just put full vacuum directly to the blend door actuator. That'll work. Buys you time to fix it properly later.

Stashing a second sensor inside the dash would work to get you up and running, if you can even find one of the things. It would not work accurately though, as it is dependent on airflow through it, through that little hole below the dash pad above the glovebox, which gets pulled through the sensor by "gentle vacuum" from the blower motor via a tube.

Dashpad removal isn't actually that hard, but I understand concerns about damaging it might keep you away from that idea.

Thanks. I wondered what that tube was for. Darn complicated system.

[jrhende6]

Hooking it to full vacuum will make it cold, but you'd need to pull and plug it for heat. People do this when that sensor gives up, and since they have gone obsolete I can't say I don't understand.

Ok. Now I have the full picture. The hot and cold lever moves the ambient air sensor which wasn't apparent to me at first.

[gadget73]

right, the lever adjusts tension on a spring inside that gizmo. Its a variable vacuum regulator that is heat sensitive. Its the BS you got in the pre-electronic era. The later electronically driven blend door is a much more accurate system, though the setup they hacked into the panther cars is not the most durable. Little plastic gears break and make the whole thing stop working. Basically they took that 1979 HVAC and slapped a small electric motor in there to "update" it without really re-designing it.

[jrhende6]

Thanks gadget73.

Final question.

Removed dash pad which wasn't too bad but it looked as though that one needs to remove front of dash to get to screws holding the ambient cabin temp sensor so I gave up. The vacuum gauge connected to big diverter actuator lays in my glove box which is interim fix for now.

I recall pictures of a project where someone had sawed a new hole and put in an ambient air temp sensor. Anyone remember that post and has the link? I would be grateful.

[gadget73]

Don't recall removing the front dash trim but its been a long time. I want to say it has two studs that the sensor mounts on and you just remove the nuts from the back side. If not, that panel is just attached with spring clips so it will pop right off.

[sly]

Yeah... remove the nuts/screws from the windshield side of the sensor. Comes right out.

[87gtVIC]

Thanks gadget73.

Final question.

Removed dash pad which wasn't too bad but it looked as though that one needs to remove front of dash to get to screws holding the ambient cabin temp sensor so I gave up. The vacuum gauge connected to big diverter actuator lays in my glove box which is interim fix for now.

I recall pictures of a project where someone had sawed a new hole and put in an ambient air temp sensor. Anyone remember that post and has the link? I would be grateful.

This one any help?

http://www.grandmarq.net/vb/showthre...uipped-vehicle

[gadget73]

betting thats what he was looking at thinking the front panel had to come off or relocate the sensor.