# 2017 1.4 turbo hvac issue



## 71mk3lincoln (Feb 6, 2021)

Still fighting my hvac issue. New control panel reccomended by the dealer. They said they think its the issue. Bought alldatadiy access and i see there is a power distribution relay associated with the hvac susposed to be on the harness. Anyone know where this will be? I want to test it and see if its my issue. 

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## Ma v e n (Oct 8, 2018)

What's your issue?


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## 71mk3lincoln (Feb 6, 2021)

Well hvac has not worked since i got it. Took it to the dealership and they had it for 2 days. Chatged me for 5 hours of labor to tell me powers getting to everything in the system but the control panel. I bought it and put it in. No change. No lights on the control panel. All fuses good. All relays tested with power to ensure functionality.. 

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## Ma v e n (Oct 8, 2018)

Test the ground circuits to the control knob assembly and to the control module (it's up above driver's side of glove box 

Beyond testing power and grounds, you can test the LIN network comm wire between the knobs and the module. If you don't find anything that way it sounds like you have a bad HVAC ontrol module. 

But having access to a scan tool to be able to ascertain what is communicating and what isn't would be ideal. 

Sounds like your dealer didn't know WTF they were doing.


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## 71mk3lincoln (Feb 6, 2021)

Can i test the lin network with a multimeter? How would i do that?


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## Ma v e n (Oct 8, 2018)

It's not the relay. Fuse 21 is the only "upstream" power source that can cause this issue. Any other power faults are gonna be related the the connectors at the HVAC components or a single wire fault after the power distribution


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## Ma v e n (Oct 8, 2018)

71mk3lincoln said:


> Can i test the lin network with a multimeter? How would i do that?


Yeah can test it end to end for resistance, and you can make sure it's not shorted to power


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## 71mk3lincoln (Feb 6, 2021)

Ok i know how to do that. I got alldatadiy access so i can find the schematic. Thanks alot. 

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## Ma v e n (Oct 8, 2018)

I posted the schematic previously didn't I?


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## Ma v e n (Oct 8, 2018)

Wait, did I misread or was there a typo? The dealer told you the issue? It's no power to the knobs?
Just jumper power to the knobs and see if they work. Terminal 1, the red/green wire in corner of the connector.


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## 71mk3lincoln (Feb 6, 2021)

Ya i planned to do that when i get home tomorrow. They said body control mod and the hvac control mod had power. Just gonna use a test probe. See if they light up. Just called dealership for shits and giggles. Asked how much the hvac control mod is...... 500 to 800 depending on which one i need. I think i may just pop the mode cirvo off and the heater core flaps cirvo off and figure out how to pin em open for windshield defrost and then jumper the blower motor with a fuse and a potentiometer. Im used to driving **** boxes anyways. Aint spending 800 on some think box. 

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## Ma v e n (Oct 8, 2018)

I'm pretty sure most of the HVAC modules are $100 or so.


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## 71mk3lincoln (Feb 6, 2021)

Not from titus will chevrolet in tacoma washington. I called em to see how much it was and the parts guy told me 600 to 800. 

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## Ma v e n (Oct 8, 2018)

ACDelco Parts



Enter your vehicle details, then search for "HVAC control module" in the "SmartSearch" box. There will probably be 4 or 5 to choose from.
Based on your cars trim level, if auto or manual AC, and if it's got autostart or not you should be able divine which one you need without the dealer (my part catalog isn't working) and then just source it via a Google search.


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## 71mk3lincoln (Feb 6, 2021)

Ok. In my alldata thing i got it says you cant swap modules around because they are specific to the car. Does this apply to hvac too or only the major modules like ecm and tcm? Sorry to blow ya up so much but i am new to working on such modern electronics. 

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## Ma v e n (Oct 8, 2018)

Solving the actual problem and potentially replacing the module are FAR easier than your proposed Rube Goldberg solution  LOL


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## Ma v e n (Oct 8, 2018)

You SHOULD be able to just pop in a used HVAC control module and have it work just fine as long as it's same part# and same equipment as your car. A new one will need to be programmed.


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## 71mk3lincoln (Feb 6, 2021)

Ok. I did find a few used on ebay. I will pull the old one and see about part numbers. Make sure i match. May even pull it apart and attack it with a multimeter. Just to be sure in my mind its bad. 

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