94 Heater Temperature Door
Thread Starter
Pro
Joined: Apr 2008
Posts: 586
Likes: 119
From: Saint Cloud, FL
94 Heater Temperature Door
'94 LT1, Auto-Climate Control:
Very recently I've noticed that (1) A/C isn't blowing ICE COLD (System Charge is good) and (2) Heat isn't blowing HOT as it has in the past (seems luke warm).
I suspect the Temperature Door is not operating based on some data I collected from the Head Unit (in diagnostics mode). The format is:
(Temp Setting), (Temp Door Position Request), (Temp Door Travel Range) obtained from the diagnostics locations 1, 34, and 31 respectively.
60, 253, 162
65, 173, 162
75, 76, 162
80, 49, 162
86, 17, 162
90, 0, 162
The data suggests that the head unit is commanding a particular door position and that the door is not moving. It looks as if the Temp Door is stuck near mid range (100 <= Range <= 200).
I collected this data this morning and have not had a chance to read over the FSM.
Has anyone had a problem with this on a 94 and how difficult is the cure? I've read where it's a major PITA for 93 and earlier models but simpler for the 94 and beyond.
[My Bad, just found related post http://forums.corvetteforum.com/show....php?t=2164739. However I'm searching for info specific to the '94.]
Very recently I've noticed that (1) A/C isn't blowing ICE COLD (System Charge is good) and (2) Heat isn't blowing HOT as it has in the past (seems luke warm).
I suspect the Temperature Door is not operating based on some data I collected from the Head Unit (in diagnostics mode). The format is:
(Temp Setting), (Temp Door Position Request), (Temp Door Travel Range) obtained from the diagnostics locations 1, 34, and 31 respectively.
60, 253, 162
65, 173, 162
75, 76, 162
80, 49, 162
86, 17, 162
90, 0, 162
The data suggests that the head unit is commanding a particular door position and that the door is not moving. It looks as if the Temp Door is stuck near mid range (100 <= Range <= 200).
I collected this data this morning and have not had a chance to read over the FSM.
Has anyone had a problem with this on a 94 and how difficult is the cure? I've read where it's a major PITA for 93 and earlier models but simpler for the 94 and beyond.
[My Bad, just found related post http://forums.corvetteforum.com/show....php?t=2164739. However I'm searching for info specific to the '94.]
Last edited by carllangford; Oct 23, 2008 at 01:44 PM. Reason: Found related post
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Based on images of '96 temp door control mechanism in the post "A/C & Heater Door Problem " and the fact that my '88 has the same mechanism, your '94 should have the same motor driven scheme.
Drop the RH hush panel and see if the control rod is still attached to the motor arm and then see if the motor tries to move the arm when you switch between 90deg & 60deg on the control panel.
Drop the RH hush panel and see if the control rod is still attached to the motor arm and then see if the motor tries to move the arm when you switch between 90deg & 60deg on the control panel.
Instructor
Joined: Aug 2002
Posts: 152
Likes: 0
From: Westerville Ohio
I replaced one of these on my '94 a few years back, it was pretty easy aside from leaning over the door jamb. Three screws and the plug-in I think. Mine was stuck with the heater door open. I bought the part through a dealership, and as I recall they had a hard time finding an exploded view that showed it. Good luck.
Thread Starter
Pro
Joined: Apr 2008
Posts: 586
Likes: 119
From: Saint Cloud, FL
I just verified temperature mix door is functioning by removing blower power module and peeking inside at the door while changing temp setting between 60 and 90.
Also there's an error in my OP: The diagnostic register that indicates door position is #24 and it is following the commanded value indicated in #34.
Guess it's possibly time to flush the heater core? I need to look for a differential in temp between heater core inlet and outlet hoses. Inlet is supposed to be warmer than the outlet, which makes sense.
Also there's an error in my OP: The diagnostic register that indicates door position is #24 and it is following the commanded value indicated in #34.
Guess it's possibly time to flush the heater core? I need to look for a differential in temp between heater core inlet and outlet hoses. Inlet is supposed to be warmer than the outlet, which makes sense.
