1990 300zx 2+2 N/A Ac and heat problems

[Camo12345123]

Hello everyone!!
I bought myself a very used z32 this Christmas and I love it except I can't defrost the windshield :/ I don't have any heat or cool. The Ac just blows whatever is outside.
Here's some basic info on the car:
-it's the digital auto climate control system
-the control pod works fine
- I can switch from defrost to face and floor, all of the actuator or motors work.
- the heater core is there (not bypassed)
-the coolent is full
-it reaches operating tempature, just a little below half on the cool side.
-I've unplugged the ambient sensor and the one inbetween the t-tops to check and see if it would blow full heat like I thought it should, no luck.
-there is no coolent leaking into the floor

If I failed to mention anything let me know! The Ac does the same as the heat. I can turn it on full blast heat while at operating temp, and then turn it on full blast cold and the temp won't change, almost as my sensors arnt reading the tempature properly. I am dying to make this car my daily, I have an 09 lancer and I'd rather drive the z any day. Even if I have to steer, shift, then wipe (manual defrost) lol!!

Some suggestions I've herd:
- maybe it's the valve that lets coolent into the heater core. (But why is there no difference between my Ac and heat?)
- maybe the control pods are bad. (Maybe but all the buttons work and it controls everything properly except the tempature)

If any of my sensors are bad will they throw codes?

Last question, where are my emergency flashers?

Thanks everybody! I'm glad to be apart of the z-team! Lol

[rgregoryb]

Emergency flasher switch on top of right control pod.

[centralcoaster33]

There is a door between the heat and AC that moves to adjust the mix. Can you verify that door is moving as you slide your temp from max cold to max hot? I think you'd be able to see the motor actuate a lever from the outside, but you'd have to be into your dash a bit. AC can be a lot of things. I'd focus on getting the heat going, then move on to AC. That'll at least get your climate circulation system up and running.

[elecfus]

basic checks are: start the car, turn on the AC, look at the AC unit, you will hear a click as the AC pulley clutch engages. click it on and off again a few times and you should hear it.
just bypass your heater valve so it blows hot air all the time then put it back when you're sick of being so toasty.
now you've checked it all, if it's still not working it could be the wiring or the hot/cold switch.


depends on which type of control pod you have. if you have the weird automatic AC climate control unit there are about 100 pages in the manual of diagnostics.

[Camo12345123]

Thank you rgreg! My button was missing but thanks to you I found my flashers!

Central, I can't physically switch from to hot to cold. I have the digital controls where you press auto and set the temp but if there's a door on these I'd be more than happy to check it

Elecfus, I would love to do the heater valve bypass, that sounds very promising in my situation! If you have any more info on that I would appreciate it! In the meantime I will be researching that!

So here's what I've found out! And this might be all my problems, I don't think my control pod is stock!! Due to the fact that my year manual says there's a "set" and "Amb" on the display and on mine it says "set" and "mode"

To do all the test I need the "Amb" there for the numbers but instead I have mode which displays a fan and a couple dashes. I have no idea what year this thing is on but they can have it back, I'm going to look into how much a stock one cost and look into this a little bit more.

Does anyone know how to post pictures on these forums or some kind of forum q/a or tutorial section? Lol

Thanks for the replays everyone and y'all are all helping me narrow this problem down!

[centralcoaster33]

Here's a link to our instruction for posting pictures. Use the preview button to confirm it's working on your machine before hitting submit...

post6602408.html?hilit=how%20to%20post% ... s#p6602408

[elecfus]

my guess is that someone inexpertly tried to disassembly the dash previously to your ownership. hence why the climate control doesnt work and why the flasher button is missing. so look out for dodgy fixes if you need to take the dash off. I've uploaded the manual. filedropper-dot-com/nissan300zx1993

as for asking about bypassing the heater valve, you just take the input coolant pipe and output coolant pipe and join them. this would only test whether or not the valve works. you could also disconnect it electrically from the control unit and give it 12V to see if it flips open the solenoid or not or suck on a vacuum line. that's just an example of how you can bypass any number of the components for diagnosis. you could disconnect the air doors as well and just hold them open to test or put a jumper in place of your AC relay so the AC clutch stays on. but the AC control unit does all of these tests anyway. it's just an easy test that I can do on any model of car to quickly tell if it's just not controlling anything in the assembly or if there's some problem with the assembly.

here's one of the diagnostic procedures from the manual.