1997 heater and a/c doesnt work... SOS!!!
Thread Starter
8th Gear
Joined: Nov 2018
Posts: 8
Likes: 0
From: Utah
1997 heater and a/c doesnt work... SOS!!!
I recently purchased my first Vette; she's a 1997 C5, 2LT with the dual HVAC system. The a/c and heat don't hardly work. I read that if the air changes speeds that it won't be an electrical problem, but who knows that could've been written by some hippy who drives foreign cars. I had the blower motor resistor replaced about a week ago but to no avail. I took her in for a second diagnostic test today and the mech claims that I need to have the HVAC control rebuilt. GM had a service bulletin put out saying that the 97-04's need that system rebuilt.The previous owner hadn't done anything about it and now I'm stuck getting it fixed.
I guess I really need to know if that's the real problem or if the dealer is just trying to screw me. I really do need that heater working, I live in Utah and it's already below 30* F in the mornings going to work. I'm open to all suggestions and I'm super desperate.
Also are there any Utah Corvette owners here... and do you have a shop or a "guy" that can help me.
I guess I really need to know if that's the real problem or if the dealer is just trying to screw me. I really do need that heater working, I live in Utah and it's already below 30* F in the mornings going to work. I'm open to all suggestions and I'm super desperate.
Also are there any Utah Corvette owners here... and do you have a shop or a "guy" that can help me.
Melting Slicks
Joined: Sep 2008
Posts: 3,138
Likes: 802
From: Espanola New Mexico
Most problems with hvac head units are resistors that were not soldered correctly, unit has to be removed and resistors re-soldered. I have done this several years ago to my 97. Recently had problems with my hvac not coming on as well, I made a fist and struck the side of the console where the hvac is located, and it came on, not very technical advise, but it came on. Hope this helps.
Drifting
Joined: Feb 2008
Posts: 1,596
Likes: 67
From: Bahama North Carolina
I recently purchased my first Vette; she's a 1997 C5, 2LT with the dual HVAC system. The a/c and heat don't hardly work. I read that if the air changes speeds that it won't be an electrical problem, but who knows that could've been written by some hippy who drives foreign cars. I had the blower motor resistor replaced about a week ago but to no avail. I took her in for a second diagnostic test today and the mech claims that I need to have the HVAC control rebuilt. GM had a service bulletin put out saying that the 97-04's need that system rebuilt.The previous owner hadn't done anything about it and now I'm stuck getting it fixed.
I guess I really need to know if that's the real problem or if the dealer is just trying to screw me. I really do need that heater working, I live in Utah and it's already below 30* F in the mornings going to work. I'm open to all suggestions and I'm super desperate.
Also are there any Utah Corvette owners here... and do you have a shop or a "guy" that can help me.
I guess I really need to know if that's the real problem or if the dealer is just trying to screw me. I really do need that heater working, I live in Utah and it's already below 30* F in the mornings going to work. I'm open to all suggestions and I'm super desperate.
Also are there any Utah Corvette owners here... and do you have a shop or a "guy" that can help me.
Thread Starter
8th Gear
Joined: Nov 2018
Posts: 8
Likes: 0
From: Utah
I've never heard or read anything about a GM service bulletin saying the HVAC unit needs to be rebuilt. I don't think GM will even rebuild them in the first place they just replace expensive parts. That hippy who wrote about the air speed changes was right. If the fan changes speed it is not the blower motor resistor. What do you mean by ac and heat don't hardly work? Use the dic to pull the codes. With key on, just press reset until the screen is blank then press and HOLD options and press fuel 4 times. It will display the codes and go back to manual mode where you can toggle thru the list by using the options button. Just press E\M to exit. Post any hvac codes. I would get it out of that dealership before they rob you blind. It could be the control unit but i seriously doubt it.
Five codes for the HVAC
B0361 H
B0363 H
B0365 H
B0367 H
B0441 H
There are also two codes for the PCM
P0650 H C
P1671 H
Two codes for the BCM
B2721 H
B2723 H
And one code for the SCM
B2177 H
Also last week one of them had both the "H" and the "C" but then I had the blower motor resistor replaced and it seems to have changed so I hope it needed to be fixed.
I'd love to not have to rely on a dealer but I don't know anybody friend or professional that can work on her. I appreciate any and all the help I can get. Thanks
Thread Starter
8th Gear
Joined: Nov 2018
Posts: 8
Likes: 0
From: Utah
I've never heard or read anything about a GM service bulletin saying the HVAC unit needs to be rebuilt. I don't think GM will even rebuild them in the first place they just replace expensive parts. That hippy who wrote about the air speed changes was right. If the fan changes speed it is not the blower motor resistor. What do you mean by ac and heat don't hardly work? Use the dic to pull the codes. With key on, just press reset until the screen is blank then press and HOLD options and press fuel 4 times. It will display the codes and go back to manual mode where you can toggle thru the list by using the options button. Just press E\M to exit. Post any hvac codes. I would get it out of that dealership before they rob you blind. It could be the control unit but i seriously doubt it.
Melting Slicks
Joined: Sep 2008
Posts: 3,138
Likes: 802
From: Espanola New Mexico
There is a small hard plastic vacuum line behind the engine's intake manifold, this is the line that supplies vacuum to operate the hvac blend doors, make sure it is not disconnected. Could be a vacuum leak under the dash somewhere as well. Hope this helps.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The AIR DAMPERS work off vacuum. Are you able to change the locations where the air comes???????? If the dampers are NOT working properly, the fan air will come out of MULTIPLE locations and you will think that the fan is not blowing the correct volume of air....
The TEMPRATURE is controlled by electric actuator motors that move Temperature BLEND DOORS. The HVAC B Series DTCs all point to issues with BOTH Blend doors. That means you CAN NOT move the blend doors.
You have to resolve that issue!! See if you can hear the blend door motors run when you turn the HVAC system OFF and Back On. They run a recalibration routine each time you turn the system on and off. You should also clear ALL the B series HVAC DTC s and see if the motors try to run and recalibrate. You should be able to hear them by listening closely to the vent areas.
Give that a try.
Bill
The TEMPRATURE is controlled by electric actuator motors that move Temperature BLEND DOORS. The HVAC B Series DTCs all point to issues with BOTH Blend doors. That means you CAN NOT move the blend doors.
You have to resolve that issue!! See if you can hear the blend door motors run when you turn the HVAC system OFF and Back On. They run a recalibration routine each time you turn the system on and off. You should also clear ALL the B series HVAC DTC s and see if the motors try to run and recalibrate. You should be able to hear them by listening closely to the vent areas.
Give that a try.
Bill
Last edited by Bill Curlee; Nov 16, 2018 at 01:31 PM.
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Thread Starter
8th Gear
Joined: Nov 2018
Posts: 8
Likes: 0
From: Utah
Is it closer to the front of the car or closer to where the driver is..
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The vacuum line has NOTHING to do with temperature changes. It just allows the system to change where the air comes out of the vents. Upper vents, Lower vents, both or Defrost.
Bill