HVAC not shutting off : draining battery

[DOCMORGY]

I was wondering if anybody else had this problem. My 97 NSX-T has decided to develop an electronic gremlin : I found out the hard way when I went to start it up to drive on a nice day (we've had very few of them lately) and the battery was dead (new battery).

Once battery was charged I then noticed that the HVAC was still operational after I had shut down & removed the key. No amount of jiggling the key in cylinder to ensure that it wasn't remaining in ACC mode was helpful. Also, my radio has decided to give up the ghost at the same time (will make for a very long boring drive over to Lynnwood soon for some more servicing...)

Has anybody else had this type of goofiness?

 

[swimmingpie]

So the fan is blowing when the car is off?

 

[warrenw]

If there has not been any after market wiring done to the car and the radio and HVAC are powered up after the key is removed, my first look would be the ignition switch.
1. Is it a high mileage car? Ignition switches do wear out.
2. If there has been after market wiring done to the car, you may have to remove or put everything back to factory to ensure it isn't the wiring changes.
3. Does anything else work with the key out? Like windows... (again, if so, ignition switch.)

 

[Vega$ NSX]

Oh man, I can feel your pain. I went through this where the fan would run after the car was turned off and the key was removed. I did the following:

1) Sent my climate control unit to BrianK to get complete refurbished. (Didn't fix it)
2) Checked/Changed all my fuses. (Didn't fix it)
3) Changed our ignition. (Didn't fix it)
4) Pulled out all aftermarket A/V equipment (Didn't fix it)
5) Checked/Changed out multiple sensors (Didn't fix it)
6) Traced back all of my wiring for anything electronic. Eventually found a wire that had the insultion rubbed off and the wire was pinched by a screw. (Problem solved).

 

[DOCMORGY]

Oh man, I can feel your pain. I went through this where the fan would run after the car was turned off and the key was removed. I did the following:

1) Sent my climate control unit to BrianK to get complete refurbished. (Didn't fix it)
2) Checked/Changed all my fuses. (Didn't fix it)
3) Changed our ignition. (Didn't fix it)
4) Pulled out all aftermarket A/V equipment (Didn't fix it)
5) Checked/Changed out multiple sensors (Didn't fix it)
6) Traced back all of my wiring for anything electronic. Eventually found a wire that had the insultion rubbed off and the wire was pinched by a screw. (Problem solved).

All's I can say is EEEKKKK : I suspect that is what will happen.
My car only has 55k on it
Stock headunit that stopped working soon after I had an iPod USA-Spec adapter added. Previous owner had added the SoS sub in passenger footwell with a big-ass amp behind driver's seat (godawful fugly - replaced w/smaller amp in trunk)
My car is FAR from stock - unfortunately - so I anticipate it will be somewhat of a pain to find...

Thanks for ideas.

 

[swimmingpie]

It sounds like some freak short circuit. I was actually looking at the wiring diagrams for this exact thing about a week ago and I noticed that even if the ccu somehow grounds the fan, it shouldn't still run with the car off because there is a relay on the hot side of the fan also.

Does this still happen if the climate control computer is removed?

You can also check the blower motor relay. Under the hood, just above the spare tire is "Relay Box A". Check the relay on the far right closest to you. That's the blower motor relay. See if you still have the problem with it removed. Check and see if the relay is broken. The relay directly to the left of it is the blower high relay. Check it too. If you don't have an extra relay to swap it with, you can just grab the horn relay which is in the middle on the row closest to the firewall.

 

[DOCMORGY]

It sounds like some freak short circuit. I was actually looking at the wiring diagrams for this exact thing about a week ago and I noticed that even if the ccu somehow grounds the fan, it shouldn't still run with the car off because there is a relay on the hot side of the fan also.

Does this still happen if the climate control computer is removed?

You can also check the blower motor relay. Under the hood, just above the spare tire is "Relay Box A". Check the relay on the far right closest to you. That's the blower motor relay. See if you still have the problem with it removed. Check and see if the relay is broken. The relay directly to the left of it is the blower high relay. Check it too. If you don't have an extra relay to swap it with, you can just grab the horn relay which is in the middle on the row closest to the firewall.

I'll give this a try since the fuse box is so easily accessible underhood (alot harder to reach inside the car). I may just give up & let the dealer dig in though that can get quite pricey...

 

[BTL3.0]

Arent the guys from Umbrelladesign in WA?? If they are close to you, you can have them take a look before you take it to the dealer. Im sure their price are better then dealership. Plus they are fimiliar with our car, thats a plus.

 

[DOCMORGY]

Arent the guys from Umbrelladesign in WA?? If they are close to you, you can have them take a look before you take it to the dealer. Im sure their price are better then dealership. Plus they are fimiliar with our car, thats a plus.

Not familiar with that entity. I've had good luck with Charles at Acura of Lynnwood. I'll try a search on Umbrelladesign though just for grins

 

[BTL3.0]

http://www.umbrellaautodesign.com/