Da Mail Man

greetings,
seems that i just started a thread this morning and now i have an actual issue!

took a 240 mile trip this morning. while at the last 20 miles of the trip, after stopping at a light, the vent outside air started blowing hot through the vents. i can switch from econ to heater to defroster and all switches fine diverting the air to their appropriate stations.

i then switched the a/c on and the compressor engaged fine and all the lines that were supposed to be cold and hot were just that.

no detectable vacuum leaks and with a cursory inspection under the hood, all appears fine with car running 180*f.

the electronic climate control seems to be working fine with the fan speed and temp display settings all changing with the press of the buttons. however, the hot air si still blowing out.

before i hit the helms, any idea where i should start looking for the culprit? i will disconnect the battery and reconnect it to see if anything "resets" (other then my radio, etc) and check the fuses prior, to be sure that nothing is or is not applicable to this situation. THANKS AGAIN.

SunCr

Remove the Blower Module on the Evaporator Housing and look inside to view the Temperature Door. Have someone operate the controls between 60 and 90. The Door should move. My feeling is it won't - probably because the plastic clip that connects it's linkage to the electric motor that controls it has broken. The connector is available at a Dealer. If that's not it, it's probably the motor. To access the motor and/or the linkage, remove the passenger's side hush panel and the ECM. Follow the troubleshooting tests in your Shop Manual under Electronic Air, Temperature Controls.

Da Mail Man

thank you sir for your assistance. the selection was on "econ" on the climate control unit with the display and selection at 60*and was never messed with (no selections made on climate control unit) at the time it started blowing the hot air as mentioned in the in initial thread.

that is strange that it would break (although, i don't doubt you) while actually having been "stationary" (no temp selection of distribution selection) for over an hour.

while in the "econ" and "cold + 60*f mode", is there "tension" on that clip holding the door either open or closed? THANKS AGAIN.

PS, merry christmas or happy holidays to everyone as it so applies.

SunCr

Clip is threaded onto the shaft and then snaps over the motor connector and it's constantly being pushed and pulled as the door is moved to maintain whatever temp is set at the controls.

Da Mail Man

thanks again for the reply. are you saying that the door is in somewhat of a constant motion maintaining air temp?...i did not know that!

i have the helms open in front of me now and where you have mentioned the "blower module on the evaporator housing", would that be located and viewed in the engine compartment?

i have the book open to page 1b 18 in the a/c section and i cannot find any pict or location of the module (what does it look like?).

the manual only shows "hook -up" for the manual and not the climate control selector"....THANKS AGAIN FOR THE RESPONSE AND ASSISTANCE.

SunCr

I don't recall a picture of the part anywhere in the Gospel according to GM (which is why God invented the Forum). See Figure 21 on 1B1-25 for a picture of the Evaporator Housing - the hole on the left side (looking forward is where it mounts.) Remove the two harness connectors and unbolt the coolant bypass support. Then unbolt the Module and look inside to view the Temp Door.

Position of the Temp Door determines how much heat or cooling air enters the passenger compartment. The motor gets its voltage from the Programmer and it has it moving the door depending on the temperature set at the Control Panel and the temperature signals from the Outside and Inside Temp sensors. Say the ambient air is 50 degrees, but the car has been sitting in the sun and the inside Temp Sensor indicates that the interior is 95 degrees and you have it dialed in for 72. The system will move the door so that you start off with a/c and as you approach 72 degrees, it will move the door to blend in some heat to keep it at that number. Should the Inside Temp Sensor drop below 72, the door will move again so that you get more heat; rise above it, and it will move to a position that provides more a/c. If you really want to give it a workout, start lowering and raising the window. The Inside Temp Sensor is mounted on the Hatch Support above you.

Use Section 8A 68 to troubleshoot the Electrical. Additional info about Electronic Air is in Section 1C. Note - if you ever have Blower Problems, Section 8A 66 has some wrong voltages for the tests they have you run and was rewritten by a Factory Bulletin. Fortunately, the numbers that they give you are close enough and most Blower problems are usually because the Module crapped out, so replacing it resolves the problem.

Da Mail Man

now i am a bit confused. 1st, like always, thank you for your assistance.you comment about "...the gospel according to gm" was priceless!

i have looked for the page in the red helms manual for
my 88 coup and there is no page "1b-125". there is however a figure #25 entitled "temperature cable routing" as apparently viewed from inside of the car. figure # 24 is entitled "control head vacuum line connections" but, is for a standard selector console, and figure # 23 is entitled "air inlet valves" on pages 1b-18 + 19.

i am still unsure as to what to remove or open to see the door or linkage or if it, whatever it is, is removed from the engine compartment on the passenger side or from inside of the car. i am assuming that i am inside the car looking under the dash on the passenger side. thanks again for your patience.

SunCr

I'm using an '89 Manual so that might explain it - Look for a figure that says Evaporator Module - Mine is figure 21, Section 1B1 page 25. Otherwise, the Evaporator Housing is on the firewall, passenger side. The blower motor is closest to the fender and the part that juts out into the engine compartment houses the Evaporator - on the left side of that part (facing forward) is the Blower Module you need to remove. Once out, you can look inside of the part that's jutting out and see the door which is closer to the firewall. There are two electrical connectors on the Blower Module. The wires I can remember are red (power), brown (blower input voltage from the dash), purple or red/black (blower output voltage to the blower motor), green (compressor clutch ground), black (module ground) and green/yellow (compressor on voltage signal from the dash controls).

Da Mail Man

How Can I Post A Jpeg Pict To A Reply To Illistrate What I Am Looking At On My Car?....thanks

pablocruise

Sorry I'm late, the holiday got in the way.


What you are looking for thru the square hole is the door inside the housing:

SunCr, does this door have 2 clips on the rod? I have this pic:

and in the yellow circle is one clip. I have seen fellow forum member brookins post in these kinds of threads a picture he took from the top side of the dash. His shows a rod with a clip also. Are these 2 seperate clips?

Da Mail Man

thanks very much for the reply and picts!! i can see where one could possibly get access to see (maybe) the clip(s) by removing the plate with the wires attached to the top of the evaporator housing.

however, i am amiss as to how you opened the evap housing without having to open it up in it's entirety. being i am just into my 1st cup of coffee, i don't recall any other access to see what you depict in the picts you have attached in my 88 except maybe from the inside.

from what your picts seem to indicate is, that the clip(s) are accessible and changeable from the outside.

i will try and send both you and "suncr" an e-mail with my attached picts. by the way, how are picts attached here or am i restricted?..THANKS AGAIN for the assistance!!

Da Mail Man

problem located!

where there is that yellow clip and "blend door" you are holding, that clip at the door is fine and in good shape.

HOWEVER, there is a rod that attaches to that clip that disappears into the car and with the use of a flashlight and mirror, i can see the end of the rod (opposite the clip you have circled in yellow) that appears to be attached to nothing.

granted, my scope of vision is limited and complicated by a "reverse" view of the area through a mirror, but, it appears that either there WAS a clip at the other end or the rod has made a clean break at the end to whatever it attached to.there appears to be a "shiney dimple" to where the rod may have attached but, i am not entirely sure.

just to be on the safe side, i tested the vacuum motor at the base of the passenger floorboard with a mity-vac and it is fine.

now comes the real challenge. where does that rod opposite the clip in your pictures attach to and how do i access it? if it is a clean break from whatever it attaches to, ya think either jb weld or "gorilla glue" would reattach it?

Da Mail Man

............anyone?...........

pablocruise

I did a little searching of my own.
Click this thread and see brookman's pic
http://forums.corvetteforum.com/show...m_id=48&arch=1

Da Mail Man

SPECTACULAR! thank you very very much and those whom added their assistance! i will try to remove the dash to acquire access to the vac motors and see what needs to be done.

any tips before i get started on this project? while i am in there, does anyone need any pictures? thank again all!!

Da Mail Man

ok, here is what's going on so far.

i had to take apart a good portion of the dash (top inc.) just to get to the ELECTRIC actuator motor (i thought this was done via vacuum). i saw that the motor has a hole in the arm of which a plastic bushing gets "pressed" into, to hold it in place.

that clip was factory split at the top. a threaded rod gets screwed into it which in turn goes through into the heater core area and attaches with a different clip to the "blend" door. apparently, the rod had either popped or slid out of the clip on the actuator motor.

after calling around to some parts houses and to a few dealers, i am told that the inside clip that attaches to the motor (not the blend door) is discontinued!. i managed to locate 2 inside blend door clips and bought 'em as spares.

what i wound up doing was to put the threaded rod back inside the clip and place a very small dab of gorilla glue on the end of it and the plastic clip. this should prevent it from sliding out or popping out. it tested fine but, i will try it again in the morning and if all is well, will
re-assemble.

i was not aware that the inside clip was discontinued. anyone know of a source for these? thanks everyone for their help.