'93 HVAC troubles after new stereo
11-12-2018, 07:00 AM
#1
Intermediate
Thread Starter
'93 HVAC troubles after new stereo
Hiya fellas:
I've done a pretty thorough search thru all the forums looking for an answer to this problem with mixed results, so here goes:
I recently removed the old Bose system and all components from my '93 40th Anniv. and refreshed with a new Jensen HU, amp and speakers. I got everything from Crutchfield, including the Bose bypass harness. All works but afterwards I noticed the HVAC control lights were permanently dim. Couldn't do anything about it at the time because I had to go overseas for a few months. I attributed it to what seems normal with this car - random things go wonky because it sits for a few months, then I drive it for a few days and it remembers it's a car and things start working again.
Just got home and with the outside temps dropping I needed heat. Got none. The HVAC controls work, I can vary the temp, fan speeds, modes, auto mode seems to work, but only cold air blows from the vents. The HVAC system was working fine before the stereo install and after (except for the dimming issue), though I admit I didn't test the heat. Now I'm wondering if the two problems are related? The stereo also won't go to night mode with the headlights on.
In my search I found references to the dimming function of the HVAC display being controlled through the factory radio. I would have thought this would be addressed by the bypass harness for the new system, but evidently not. On a related note, seems the C5 and C6 guys have the exact same issues! One problem with all the old threads on this is there is lots of "I have a problem" and "try this, this might be the problem" but no "this is what fixed the problem". The threads have no closure!
I found multiple references to the wire in the factory harness from the Bose system controlling the dimming to the HVAC display, but no fix as to how to reconnect the wires or bypass the bypass to restore function. I'm also leaning to think that the heating problem is also related since the HVAC system was working fine before. I have cleaned the contacts in the HVAC control unit but I haven't tested the blend door function yet - that's up next.
Any thoughts? Advise? Fixes?
Thanks,
Mark
I've done a pretty thorough search thru all the forums looking for an answer to this problem with mixed results, so here goes:
I recently removed the old Bose system and all components from my '93 40th Anniv. and refreshed with a new Jensen HU, amp and speakers. I got everything from Crutchfield, including the Bose bypass harness. All works but afterwards I noticed the HVAC control lights were permanently dim. Couldn't do anything about it at the time because I had to go overseas for a few months. I attributed it to what seems normal with this car - random things go wonky because it sits for a few months, then I drive it for a few days and it remembers it's a car and things start working again.
Just got home and with the outside temps dropping I needed heat. Got none. The HVAC controls work, I can vary the temp, fan speeds, modes, auto mode seems to work, but only cold air blows from the vents. The HVAC system was working fine before the stereo install and after (except for the dimming issue), though I admit I didn't test the heat. Now I'm wondering if the two problems are related? The stereo also won't go to night mode with the headlights on.
In my search I found references to the dimming function of the HVAC display being controlled through the factory radio. I would have thought this would be addressed by the bypass harness for the new system, but evidently not. On a related note, seems the C5 and C6 guys have the exact same issues! One problem with all the old threads on this is there is lots of "I have a problem" and "try this, this might be the problem" but no "this is what fixed the problem". The threads have no closure!
I found multiple references to the wire in the factory harness from the Bose system controlling the dimming to the HVAC display, but no fix as to how to reconnect the wires or bypass the bypass to restore function. I'm also leaning to think that the heating problem is also related since the HVAC system was working fine before. I have cleaned the contacts in the HVAC control unit but I haven't tested the blend door function yet - that's up next.
Any thoughts? Advise? Fixes?
Thanks,
Mark
11-12-2018, 06:36 PM
#3
Hiya fellas:
I've done a pretty thorough search thru all the forums looking for an answer to this problem with mixed results, so here goes:
I recently removed the old Bose system and all components from my '93 40th Anniv. and refreshed with a new Jensen HU, amp and speakers. I got everything from Crutchfield, including the Bose bypass harness. All works but afterwards I noticed the HVAC control lights were permanently dim. Couldn't do anything about it at the time because I had to go overseas for a few months. I attributed it to what seems normal with this car - random things go wonky because it sits for a few months, then I drive it for a few days and it remembers it's a car and things start working again.
Just got home and with the outside temps dropping I needed heat. Got none. The HVAC controls work, I can vary the temp, fan speeds, modes, auto mode seems to work, but only cold air blows from the vents. The HVAC system was working fine before the stereo install and after (except for the dimming issue), though I admit I didn't test the heat. Now I'm wondering if the two problems are related? The stereo also won't go to night mode with the headlights on.
In my search I found references to the dimming function of the HVAC display being controlled through the factory radio. I would have thought this would be addressed by the bypass harness for the new system, but evidently not. On a related note, seems the C5 and C6 guys have the exact same issues! One problem with all the old threads on this is there is lots of "I have a problem" and "try this, this might be the problem" but no "this is what fixed the problem". The threads have no closure!
I found multiple references to the wire in the factory harness from the Bose system controlling the dimming to the HVAC display, but no fix as to how to reconnect the wires or bypass the bypass to restore function. I'm also leaning to think that the heating problem is also related since the HVAC system was working fine before. I have cleaned the contacts in the HVAC control unit but I haven't tested the blend door function yet - that's up next.
Any thoughts? Advise? Fixes?
Thanks,
Mark
I've done a pretty thorough search thru all the forums looking for an answer to this problem with mixed results, so here goes:
I recently removed the old Bose system and all components from my '93 40th Anniv. and refreshed with a new Jensen HU, amp and speakers. I got everything from Crutchfield, including the Bose bypass harness. All works but afterwards I noticed the HVAC control lights were permanently dim. Couldn't do anything about it at the time because I had to go overseas for a few months. I attributed it to what seems normal with this car - random things go wonky because it sits for a few months, then I drive it for a few days and it remembers it's a car and things start working again.
Just got home and with the outside temps dropping I needed heat. Got none. The HVAC controls work, I can vary the temp, fan speeds, modes, auto mode seems to work, but only cold air blows from the vents. The HVAC system was working fine before the stereo install and after (except for the dimming issue), though I admit I didn't test the heat. Now I'm wondering if the two problems are related? The stereo also won't go to night mode with the headlights on.
In my search I found references to the dimming function of the HVAC display being controlled through the factory radio. I would have thought this would be addressed by the bypass harness for the new system, but evidently not. On a related note, seems the C5 and C6 guys have the exact same issues! One problem with all the old threads on this is there is lots of "I have a problem" and "try this, this might be the problem" but no "this is what fixed the problem". The threads have no closure!
I found multiple references to the wire in the factory harness from the Bose system controlling the dimming to the HVAC display, but no fix as to how to reconnect the wires or bypass the bypass to restore function. I'm also leaning to think that the heating problem is also related since the HVAC system was working fine before. I have cleaned the contacts in the HVAC control unit but I haven't tested the blend door function yet - that's up next.
Any thoughts? Advise? Fixes?
Thanks,
Mark
I am going to throw this out there because a similar thing happened to me but it happened during a water pump change. I disconnected the battery for a day until I completed the water pump install. Upon reconnecting my battery and starting the car the Blend Door Actuator which is mounted under the passenger side dash tried to cycle (tries to cycle back to home but can't get there because of a cracked gear). The nylon gear was cracked and was slipping on the main metal shaft it was pressed onto. This resulted in only cold air blowing through the vents but no heat no matter how hot I set the control. The Auto Fan light was also flashing which led me to check for codes, this did point to the Blend Door Actuator as a possible cause. It was a coincidence but disconnecting the battery exposed the defect.
So if by any chance you happen to disconnect the battery or the battery went low and the Auto Fan light is flashing then you may want to check the Blend Door Actuator.
Good Luck!
11-12-2018, 09:19 PM
#4
Intermediate
Thread Starter
I pulled the HU and yes, there is an orange wire and no, it is not hooked up to anything. I will have to look up in the stereo installation instructions to figure out why I didn't connect it. I can select night mode via the menu on the stereo so I can dim it but it's a pain to do it all the time.
11-12-2018, 09:28 PM
#5
Intermediate
Thread Starter
Hi Mark,
I am going to throw this out there because a similar thing happened to me but it happened during a water pump change. I disconnected the battery for a day until I completed the water pump install. Upon reconnecting my battery and starting the car the Blend Door Actuator which is mounted under the passenger side dash tried to cycle (tries to cycle back to home but can't get there because of a cracked gear). The nylon gear was cracked and was slipping on the main metal shaft it was pressed onto. This resulted in only cold air blowing through the vents but no heat no matter how hot I set the control. The Auto Fan light was also flashing which led me to check for codes, this did point to the Blend Door Actuator as a possible cause. It was a coincidence but disconnecting the battery exposed the defect.
So if by any chance you happen to disconnect the battery or the battery went low and the Auto Fan light is flashing then you may want to check the Blend Door Actuator.
Good Luck!
I am going to throw this out there because a similar thing happened to me but it happened during a water pump change. I disconnected the battery for a day until I completed the water pump install. Upon reconnecting my battery and starting the car the Blend Door Actuator which is mounted under the passenger side dash tried to cycle (tries to cycle back to home but can't get there because of a cracked gear). The nylon gear was cracked and was slipping on the main metal shaft it was pressed onto. This resulted in only cold air blowing through the vents but no heat no matter how hot I set the control. The Auto Fan light was also flashing which led me to check for codes, this did point to the Blend Door Actuator as a possible cause. It was a coincidence but disconnecting the battery exposed the defect.
So if by any chance you happen to disconnect the battery or the battery went low and the Auto Fan light is flashing then you may want to check the Blend Door Actuator.
Good Luck!
Next problem - the actuator on the '93 is on top of the heater core box, not the bottom, and supposedly the whole kit & kaboodle has to come out to replace the actuator. Heater core, a/c evaporator, inside and outside boxes, everything! My respect for the engineering staff at GM might hit new lows if this is the case!
Mark