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The HVAC lights on my 98 vette stay on after I park it after all the other lights shut off. I haven't seen how long it it is but I'll see if they are on tomorrow. The car is currently in my garage on a charger. Its a 98, the dual climate control. Haven't noticed it before and no codes in the HVAC? I searched and found one thread where they ended up replacing it and another one that said the condition just "went away".
A friend had this EXACT some problem. All interior lights would go off except the dual control HVAC unit. I determined it had to be the actual HVAC unit was not acting on the request from the BCM to shutoff. We swapped in a spare I had and it fixed the problem. There are 3 circuit boards in there and I had no idea where to look to see if I could fix it. The old unit just sits on his shelf now.
That related Thread may have been us. Would like to know if it was someone else.
Here is how to access it for removal. Just takes about 20-30 minutes to get to it the first time. If you have a manual tranny you DO NOT have to remove the shifter **** and boot. Just release the shift boot from the console and rotate it and it will allow you to remove the console without removing the **** and boot.
This guidance goes beyond what you need to remove the HVAC unit so you can stop once the console bezel is removed.
A friend had this EXACT some problem. All interior lights would go off except the dual control HVAC unit. I determined it had to be the actual HVAC unit was not acting on the request from the BCM to shutoff. We swapped in a spare I had and it fixed the problem. There are 3 circuit boards in there and I had no idea where to look to see if I could fix it. The old unit just sits on his shelf now.
That related Thread may have been us. Would like to know if it was someone else.
Here is how to access it for removal. Just takes about 20-30 minutes to get to it the first time. If you have a manual tranny you DO NOT have to remove the shifter **** and boot. Just release the shift boot from the console and rotate it and it will allow you to remove the console without removing the **** and boot.
This guidance goes beyond what you need to remove the HVAC unit so you can stop once the console bezel is removed.
Okay I've got it out. The board with the lights looks good but ill double check do you think its something to do with the power supply board? I'll look at that tonight! Thanks for all the help
The way I believe the dimming should work (via the FSM) is by the BCM varying the illumination voltage from 12 V to 0V. At least that is what the schematic indicates. You have to look at not only the HVAC connector pin out but also look into the Interior lighting volume. With that said, if the BCM varies the voltage then just changing my friends unit should not have fixed it. That is where the FSM again fails to fully explain how things actually work. As a result it must be related to the serial bus.
This is pin C16 which is fed from the BCM. Here is the connector in two parts. It could be the BCM but I hope not.
Thanks for all the great info! I'm going to take a look at it one more time but it would appear the bcm if fine (I actually have 2 so I swapped them and the same issue). I'm going to look at the HVAC controller closer and see if I can see a visible issue. It was working fine, noticed one of the leds I soldered on went out so i puller it out then re soldered it then I had the issue. So I probably messes it up some where. I'm suspecting I had the heat to high. Another interesting note is that after being on for a couple days the red leds are all good but the two blue ones I put in are out? Just an interesting observation
Just in case anyone else is having this issue in the future, the power board in the HVAC unit was the culprit. I messed around with it, checked numerous solder joints and narrowed it down to the power board (the one without the lights, *****, screen, etc.). I was not able to fix my power board but I had an older HVAC unit that one of the dials wasn't working right. (another rare and un-explainable occurrence) swapped the power boards out and bingo! she worked.
12-29-2014, 10:16 PM
HVAC lights stay on
