Climate Control ECU

[Ryoma]

The control unit for the HVAC in my '91 NSX is behaving oddly. It works, but then shuts off, or sometimes won't turn on at all. When working it blows the appropriate temperature air, and doesn't seem to be shutting down for any reason (like overheating, freezing up, etc.). I am not certain but possibly the fan isn't operating correctly all the time, i.e. blowing only on high, but the intermittent nature of the problem makes it hard to be sure. I pulled the unit and disassembled it but to no avail. After reinstalling it, I ran the self-diagnostic on it (activated by holding down buttons on ignition) and it did not deliver any codes. I could not get the other diagnostic to run - the one with setting the temperature to min for 1 minute and max for 1 minute, etc.

I am just wondering if any of my fellow NSX owners have had this problem or similar ones. The dealer wanted $990 to replace it, and they never even opened the console. I already priced the part at Gunn in San Antonio - right under $600. I just want to be sure I have tried everything first. Also, does anyone have any idea if it is likely someone could service the unit itself?

Thanks for any and all input. I've only gotten this far thanks to the dedication and helpfulness of everyone maintaining and contributing to the great NSX websites.

 

[Lud]

Since the unit is self-contained and expensive, the first thing I would try is swapping it for a known-good control unit. It is extremely unlikely anyone will be able to properly service the control unit.

If a known-good unit does not fix the problem, you may have a wiring or other problem.

If it does fix the problem, at least you know you're replacing a part that really is bad.

You can probably pick up a working control unit from a salvage yard for a good bit less than new.

[This message has been edited by Lud (edited 27 April 2001).]

 

[Ryoma]

I finally got my new AC controller and found time to install it. It seems to have fixed the problem - I say seems, because the weather in Houston is so nice that I have yet to use the thing at all! I did test it some and it works perfectly.

I really encourage other owners to do the work themselves if faced with the same problem. I ordered the part from Gunn Acura in San Antonio for $551 and had zero problem installing it. Sterling McCall wanted $990 total to do it. Taking the center console out was much easier than I had expected.

[This message has been edited by Ryoma (edited 18 May 2001).]