Weird AC and Headlight issue

The two-digit codes you're getting from the HVAC system are only for the HVAC system. They won't illuminate your headlight issue any. That might just take some old-fashioned multimeter work.

 

The only way I could see a headlight and the AC having anything in common would be for them to share a wire run or a power source. How that could be affected by light or temperature, I'm not sure.. I've learned that nothing is impossible. This could be interesting.

Do you have HID or halogen headlights? If you have fog lights, the car also has HID headlights. No fog lights then the car has halogen style.

Does the AC work at all during the day? Perhaps works ok when the car is cool (or first started for the day), but then drops out when the engine is hot?

 

I have seen intermittent AC operation be caused by failure of the inverter cooling pump. Failure (or weakening in some cases) of this pump loses (or lowers) coolant flow to the inverter. This causes the inverter to run at higher than normal temperature. The AC compressor is essentially powered from the inverter, so the car turns off the AC to reduce heat load at the inverter. It may be worth checking out the inverter cooling system, as if this is happening, it rarely causes any codes or faults until the pump totally fails or the inverter totally overheats. This situation has led to many people throwing a lot of money at the AC system when the real problem is the inverter cooling water pump or coolant loop. This pump is located directly behind the driverside headlight.

 

Suggestion: fill a small bucket with water. Put your tools in it. Put the bucket in the freezer, and let it freeze solid so you won't be tempted to grab the tools and start taking things apart.

While that's happening, just curl up with the 15 pages of code B1423 troubleshooting steps in the repair manual (more info), and read through them, getting familiar with the sequence of things to test to figure out what's going on. Then thaw out the tools and have at it.

 

Chap has a point. Somehow I missed the codes you mentioned earlier. I tend to just skip over any 2 digit code info. But a 1423 kind of points you in a good direction to go....assuming it's a legit code.

I'm pretty sure the 1423 code pretty much says pressure too high or pressure too low, so this:

We had the AC serviced and the mechanic is stumped. All is good as far as pressure and Freon

may not be true

Has anyone been adding to it? Are all components clean? Have you tried it in both recirc and non-recirc modes? varying fan speed? Is air always blowing out of the vents, but not always cool?

 

23=1423=B1423

B1423 is the true code. That 2 digit stuff is just abbreviations

Just like 21 is B1421

Are you confident the inverter cooling water system is good to go? Do you have any apps (similar to hybrid assistant) and a Bluetooth OBD device you could use to monitor inverter temps while driving?

 

If it helps any, the two-digit codes you can retrieve from the HVAC in the corner of the MFD are versions of five-character actual DTCs. The 23 corresponds to the trouble code B1423, which you can find in the manual. Sorry if that wasn't clear.

Note that not all of the ECUs have such a simple correspondence between their shortened codes and DTCs. For the HVAC you can more or less take your two-digit MFD code and stick B14 in front. That is not always the case for, say, brake or airbag blink codes, which pretty much have to be looked up. They'll appear in the manual following the corresponding DTC, separated by a slash.

Even though B1423 may have a one liner "fortune cookie" that says something like pressure high or low, the fortune cookies all have to be interpreted using the question "why would the ECU think that?" and the answer to the question can always include faulty sensors, wiring, electrical connections, etc., as well as the possibility that the sensor reading is right.

The workup pages in the manual are intended as an efficient way to make the necessary tests to sort all those possibilities out.

jinx

 

The swamp cooler thing is just the compressor turning off and the moisture on the evaporator burning off. There is an AC section in techstream it shows temperature, humidity and other things I can’t remember. I would get and use techstream before you wrench on anything. Is there a puddle of water under the car when you run the AC?

 

Low pressure makes sense. If there's not enough coolant, the evaporator ices up and stops blowing cold and blows sort of cool and humid. Once the ice melts, it blows cold again till that coldness freezes the condensation on the evaporator again. And round and round you go.

 

Somebody should check me in the manual, but I think in a Gen 3 what you're seeing may actually be a pressure transducer.

I think in your Techstream data list you can actually view pressure, not just a low or a high switch.

Design in a transducer, you've as good as got both switches.