Climate Control Unit Not Powering On...

[sneil]

Need help on this one as I cannot figure how to fix it. The climate control unit in the dash is not powering up, no display and nothing comes on fax etc, a/c when a turn the knobs. It seems like the fuse (or relay?) is gone but then I checked these:

high power fuse (front compartment) 30a - ok
clock fuse (front compartment) - 7.5a - ok
Fuse 4 (under drivers dash) - ok

Not sure what to do next. Everything else seems like it is working, radio, tcs, clock, dash etc. Can it be the unit itself? I do not have another to test/troubleshoot it.

 

[Old Guy]

By clock fuse, you mean fuse #33 ? If so, then you have checked the correct fuses (fuse 33 and fuse 4). One last fuse to check, #38 (in main relay box); however, I believe that one only controls the CCU illumination and doesn't stop it from working.

If all the fuses are OK, then you need to download the section of the service manual dealing with the climate control and do the diagnostic (Chap 22 pg 34 in the 1997 service manual) where you check the functions on the wiring terminal plug. This requires removing the CCU. The only thing the diagnostic really checks is the status of the 12v supplies and the ground connections to the CCU. If everything checks out on the 'car' side of the terminal plug, then your CCU is most likely dead and you need to consider sending it off to Brian K or some other repair service. Unless you are handy with electronics, there are no user serviceable bits in the CCU.

 

[sneil]

Thanks for the info. Yes I think it was 33 in the front compartment fuse/relay box and #4 under the dash drivers side. I will have to check the other one you mentioned, #38 . Is that one in the same main relay fuse box (5 over from 33)?

Also, do you have info on diagnosing (I assume is it voltages etc at each pin from the car side...?) on what to do and the voltages? Thanks for all the help, I'm going to check the fuse now...

---

Just checked so and the fuse #38 is ok..

 

[Old Guy]

Also, do you have info on diagnosing (I assume is it voltages etc at each pin from the car side...?) on what to do and the voltages? Thanks for all the help, I'm going to check the fuse now...

If the CCU only had a few connections to it, I could probably describe the test points; however, it has two fairly large terminal plugs and each has a bunch of wires in it. You need to download a copy of the climate control section of the service manual. Get the early version 1991-92 not the later 97-2005 version as the later version is missing the sections you need. You need the pin out diagram for the terminal plugs and the test procedure. The test procedure will tell you which pins to check (you will need a multimeter style tester). There are links to the manual on the NSXPrime wiki page (or buy a manual which is the best investment if you plan to keep the car).

 

[sneil]

If the CCU only had a few connections to it, I could probably describe the test points; however, it has two fairly large terminal plugs and each has a bunch of wires in it. You need to download a copy of the climate control section of the service manual. Get the early version 1991-92 not the later 97-2005 version as the later version is missing the sections you need...

Thank you that helps me out. I have the 500 pg manual in pdf and will check out the diag section for the ccu. Pulling the ccu is fun Thx again all for the help will post back on my results.

 

[Larry Bastanza]

Just send the unit out the BrianK and have him fix it........