CHEVY LUMINA 1993 HVAC

Claude

Hi there,

I saw tyhat there are already multiple discussions on Luminas but i have not found the right Q&A.

Maybe someone can help me?


-My Problem (it is a known problem i noticed) is that my different vent compartments do not switch properly air is
coming out only thru the center vent outlets.

(like in many discussions it has to do something wioth the vacuum. i found the vent controll unit and the blower engine
but I canot find the vac reservoir ther might be the issue ?)

-pushing the A/C button the little light in the buttopn does not go on

-another thing is my engine tempertur ist when the scale is between 100 and 260 it keeps the temperature between 180 &220 when driving smoothly it keeps it mostly at 180 ( going quicker qnd pushing it it goes up to 220 +-.


so my question is:

-does anyone know where to locate the vacuum reservoir?
-I checked the A/C relay it works but ther is for sure a fuse for the A/C ?
-concerning the temperature should i replace the engine coolant ? it may have loosen the function over time period?


I'm from Luxembourg, Europe and there aren't much people who work on these cars.
I got the only Lumina in Europe apparently ( according to the µLuxelbourgish register ofice)

I really appreciate if anyone can help me


Greetings from Luxembourg

Claude

imidazol97

I am guessing how your system on that model should work. I am more familiar with 1993 Buick leSabre and up vehicles. If you've taken off the underdash plastic covers, you should see vacuum modules that have a line to them and they are actuated to move the doors inside the actual heater box.

The vacuum actuators have a rubber or plastic diaphragm inside that moves when vacuum is applied and the diaphragm pulls a rod. You can insert your finger on the back side of the vacuum module through a hole and push the diaphragm and move it and the rod. If it won't move, then you likely have a broken part inside the heater box itself.

The car should be designed so that when there is NO vacuum the air goes to the defroster with a small amount to the floor for heat. The defrost for the windshield is a safety item when the vacuum doesn't work.

Yours should be defaulting to that when the engine is NOT running.

The vacuum reservoir likely is a black plastic sphere the size greater than a baseball. It may be behind the front wheel and can be seen looking up from underneath.

There also was a problem with some models that a connector for the lines on the heater box for the vacuum motors that switch defrost to dash, floor to upper dash/defrost, and recirculate at the control box for the switching would soften and be sucked shut. But that wouldn't keep the defrost from being the default when there is NO vacuum. I think you have a different problem.

http://www.imcool.com/articles/aircondition/fix_vacuum_line.htm

There are several different sites selling GM parts that have diagrams.
gmpartsdirect.com
gmpartsgiant.com

and many others. Search for gm parts using google or yahoo.

However, when I looked the diagrams for 1993 lumina were not very helpful.

You might benefit from an authentic factory service manual authorized by GM
and sold by helm helm.inc at the time. Many are available on ebay.com
There are, however, fakes out there. And you need to know how many volumes.
In this case it appears there were two basic volumes.

https://www.ebay.com/itm/Original-1993-Chevrolet-Lumina-Book-1-Repair-Service-Shop-Maintenance-Manual/113962182204?hash=item1a88ace63c:g:6AQAAOSwGzBdyY-F

https://www.ebay.com/itm/1993-Chevrolet-Lumina-Factory-Service-Manual-Book-2-Emissions-Electrical-Diag/202752002495?hash=item2f34f609bf:g:SvYAAOSwVLVdS0L2

The factory service manual is a two part manual. Here are inexpensive used books. BUT one does not ship outside US. Other one does.

https://www.ebay.com/itm/1993-Chevrolet-Lumina-CAR-Repair-Service-Manual-Set-DEALERSHIP-OEM-BOOKS-1993/400725826885?_trkparms=aid=555018&algo=PL.SIM&ao=1&asc=40719&meid=dcea19e8bee24f28b440337c249498be&pid=100005&rk=12&rkt=12&mehot=lo&sd=121346887741&itm=400725826885&pmt=1&noa=0&pg=2047675&_trksid=p2047675.c100005.m1851

You do not want the one on ebay that says Lumina APV. I think that was a minivan...