No power at HVAC control panel?

Hello, can you give us the exact codes? This way we can look up the code setting criteria and other information. But looking at the wiring diagram, the HVAC control module and the Humidity Sensor get powered up on the same feed wire coming from Fuse 99 10amp. So, see if that fuse has power and take it out and see if it looks like it got hot, or if it is blown you may have had one of those two modules short out. If it has power with the key on, next check at the back of the HVAC module on pin 2 and pin 3 of the Humidity sensor for power. If that fuse is blown, that's the cause of your lost comms. If the fuse blows again, then there is a short to ground somewhere on that pink/green wire.
That dotted line highlighted is a connector there (1310), and since the pink/green wire is pin 31 on that connector, its most likely a bulk connector with a lot of wires running through it. We can use that as a testing point if there happens to be a short to ground on the circuit.
I think you're going to find you are just missing power to those two modules, if there was an actual communication issue, you would have codes for the other modules on the LIN bus that the Humidity sensor communicates on as well as other CAN bus codes because that's the network that the HVAC communicates on.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

U0164 and U1190.

And I have checked all the fuses and I took the TIPM out and checked all the connectors and pins to be sure there was no corrosion or blown fuses. I actually checked those things before I replaced the HVAC control panel and the humidity sensor.

Did you check for power on pin 2 of the HVAC control (pink/green wire) for 12 volts? Its also pin 2 on the Humidity sensor, should be 12 volts as well. You have to verify it with a multimeter and make sure its a full 12 volts. If theres voltage drop on that wire and its only getting 9 volts for example, it wont be enough for the module to communicate. The LIN bus from the Humidity sensor is a 0 to 12 volt signal.

https://www.2carpros.com/articles/how-to-use-a-voltmeter

I have not. I only checked the power and ground wires on both. I will check them this evening after work and give an update. Thanks

Which power and ground wires did you check? The red wire on the HVAC? The pink/green wire is the one you need to go after; it powers both those modules from fuse 99 on the same wire. It's and Ignition switch feed.

That's correct.

I checked the power at the humidity sensor, the HVAC control module and the HVAC control panel. All showed power. But I was only using a test light.

Okay, go after the pink/green wire next with the Key On.
You haven't lost comms with any other modules and that one power wire ties the 2 modules together,
Do you have an oscilloscope?
The 2 modules run on different networks, the HVAC module has lost its comms on the Interior CAN bus network and the Humidity sensor communicates on the LIN bus, they are completely different signals, that's why I think there is a loss of power on that Ignition feed wire, if they are both missing power we'll need to trace it back to fuse 99.
It also goes to this in-car temperature sensor. it might be that the temperature sensor is shorted out and pulling the 12-volt feed down. so you might have to unplug that at some point. I'll try to find its location.
The last 4 diagrams are the in-car temperature sensor.. Should have the same Pink/Green wire running to it with 12 volts.
Okay, the temperature sensor is not on any network, its hard wired in, so its just like a thermistor that changes resistance with temperature. Just like a Coolant Temp sensor, so it could pull down the 12 volts without potentially blowing the fuse.

So, I have 12 volts at the red wire on the humidity sensor and the HVAC control module. I have 12 volts at the green/pink wire on the HVAC control module and only 9 volts at the green/pink on the humidity sensor.

On a side note, rechecked all the fuses. Not sure if it should have power or not, but the fuse for the PCM 10 amp is grounded on both sides.

I noticed today on the way home from work, my auto headlights came on in the garage and never went off in the sunlight.

And this morning headed to work, remote start will now only run a few seconds and disables.

Okay, so are you meaning the pink wire with a green stripe at the humidity sensor only has 9 volts? The red wire is a battery feed that should be hot at all times, Its probably to keep memory in the Hvac and other modules. I will look into the PCM fuse today. When you say grounded, you can hook a test light to battery positive and it will light the test light, ? or how are you testing and determined its grounded? Also do you have Start/Stop enabled? And is your remote start an aftermarket installation?
The Sun Sensor runs off the Hvac module, that is why your headlights are now malfunctioning. Whatever is happening is progressively getting worse.
Does the PCM fuse have a number too, I don't see one labelled PCM, I'll keep looking, but there might be a number on the fuse box label as well..

F72 is the fuse number. And I checked it with the test light. And it shows grounded on both sides when i hook to the positive battery terminal. I was just checking fuses for the third time and using a test light this time. And yes, the pink wire with green stripe has 12.46 volts at the hvac control module and that same wire has 9 volts at the humidity sensor. And I'm not sure about the start/stop being enabled. I haven't changed anything though. Where would I find the place to check that?

Do you notice it when you come to a stop? If you have the A/C off, the engine will turn off and start back up when you let your foot off the brake pedal. You may not have it or be noticing it. I think it happens less with the A/C on. It's a feature to save on gas, etc. I was just curious about that. I'll check on that fuse and get back to you. It's good to test with a test light because it puts somewhat of a load on the circuit. But if you only have 9 volts on that pink/green wire, that's a problem, there's a corroded connector or bad pin fitment issue going on. You can check the pink/green wire at the in-car temperature sensor too. It's under the panel right under the steering wheel, see if you have 9 volts there too. If so, try unplugging it and check the connector with it unplugged for voltage. You'll notice in the 3rd diagram, right next to the temperature sensor is the Sun Sensor and pin number 1 is your auto headlights signal wire. That's why there's an issue with the headlights acting up.
Okay, it appears fuse 72 will only be hot while cranking, and it goes to the Starter motor, so that's why you're reading ground on both sides of the fuse. I think it would light the test light if you cranked the engine over. It looks like you're getting ground through the starter motor, so we won't worry about that right now, we need to concentrate on these 9 volts and trace that down.

Oh no. I don't have that for sure then. I'll check the voltage at that sensor voltage as soon as I get off this ambulance and get back home this evening. Thanks!

Ok so your hvac is not working though correct? You have power to it but not functional, I think we have a bad Ground here.. Ill have some more things for you to test when you get home.

That is correct. I have power to it and it's got 12 volts. But I can't turn on the heat, ac, defroster or the vent fan. I can even hit the climate control on the Unconnect and it pulls up the heated seat and heated steering wheel but doesn't give me any of the ac options. And if I hit the ON button on the screen and still nothing.

Oh okay, so you have some kind of smart display(Vehicle System Interface Module) to control different systems in the truck, and you have a scan tool i assume,, what kind of scanner do you have? Can it do full system scans of every module?

And before you replaced the Hvac and humidity modules what was happening? Your initial post says "No power at Hvac control panel".
Also did you do any type of verification test on the new hvac module, or any programming?
There is a verification test listed for new modules, Im also going to have you check the actual CAN bus network with a multimeter to see if there is activity coming out of the module, separate from the rest of the network.

You can answer all this after work,, Im just going to post as I go here.

I replaced the dual climate control HVAC panel and the humidity sensor based on the codes and the fact that I had power at the plug at the control panel but no power in the control itself. And I used new parts and not used ones so I didn't check them. I have an alpha obd2 scanner/programmer and I paid for the extra access. So I can scan all the systems on the truck. The only thing it will not let me access is the hvac system. It says it can not communicate with it.

Okay, I've narrowed it down to a couple of connectors. This connector I310 is a bulk connector in a place that can possibly be exposed to moisture intrusion, down by your left leg as in diagram 1. It has the power feeds to the Hvac Module, Humidity sensor, In-car Temperature sensor, plus an Ignition switch feed, K Line network, CAN C Bus Network Low side, for the Keyless ignition Node Module and Radio Frequency Hub Module (for remote start). I don't know what else runs through this connector, so I wouldn't just pull it apart, It may have SRS (airbag) wiring running through it. And you don't want to set any of them off. But this connector may have corrosion inside of it effecting some pins and causing voltage drop across it. (Diagrams 1 through 4)

The 2nd possibility is a Ground G212 although it doesn't explain the 9 volts reading. Its Ground for the Hvac module, humidity sensor, In-car temp sensor, And the Keyless Ignition Node Module. (diagrams 5 through 7).
I found a bunch of safety recalls I'm going to post as well.

Okay, with the 9-volt issue, I think checking the Connector I310 first would be a good idea, If you had a bad ground to any of these modules, you would still have a 12volt feed depending on where you were using for ground with the meter. The 9 volts makes me suspect a connector issue or splice, but since you are now having issues with the remote start, which runs through the I310 connector too. The network in this truck is pretty complex, but it's tough to say exactly what's going on since you have 12v at the hvac module, The last page above is the verification for the hvac module.
At this point I would try erasing all the codes and see what comes back right away. You can also try the wiggle test with that connector and see if any hvac control comes back. It's the one connector that ties all the issues together, my next test would be to de-pin the CAN bus network pins out of the hvac module and keep it powered up by check if a signal was coming out of the module itself, that way none of the network would be connected and you could see if anything was coming out of the CAN bus pins. I assume you have tried erasing the codes after the new modules were installed. And by the way there are 9 safety recalls I have for you. Pages 1 and 2 go together, and 9 and 10 go together. These are Safety Recalls, that's why I am posting them, if they were regular recalls I wouldn't be as concerned.

So, an update. Pulled the I310 pin. Didn't see any noticeable issues. Plugged it back up and cleated the codes. Everything started working properly and all the codes are gone. Maybe it will last. Big thanks!

Okay, if that's where the issue was, and there was no corrosion, then it's a pin fitment issue on that connector. Normal vibrations from driving and the engine can cause things to loosen up over time, if the issue shows up again go right to that connector and see if the female pins are spread or loose at all. They're probably small pins, communication pins usually are since they carry very low current. Glad it's working for you though.

I feel so fortunate to have stumbled upon this site. I too have the same two codes U0164 and P1009 after replacing the battery on my 2015 RAM Laramie ecoDiesel. I cannot power on the climate control module, nor will anything toggle on the mid control cluster underneath the main center screen.
A couple of questions - 1. Where is the HVAC control module located and 2. Where is connection 1310?

Thanks

This is an old post from almost a year ago, and his codes were U0164 and U1190. His vehicle has a different design then yours does. We would need all the vehicle information to begin with. I dont see an connector i310 for your AC Heater Module and In Car Temp Sensor, it looks to be i311 possibly in your vehicle, but you are better off to start a new post with your question and the codes you are getting. Add year, make, model, engine size, turbo or non turbo. That way this issue can be addressed correctly. The wiring colors are most likely different as well. I know its only a 2 year difference, but technology is advancing faster each year. Start a new post and someone will be able to help you with a fresh start. This case youre posting to was very complicated. We are instructed to have different vehicles to start a new post.