HVAC system not working

2002 DODGE RAM
90,000 MILES • 3.7L • V6 • 2WD • AUTOMATIC
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MIKE READING
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I disassembled the dashboard to replace heater core. the HVAC system worked before I took it apart, but now the whole system is dead. it looks like all connections are together and the fuse for system is okay. the light for showing A/C on/off lights up and goes off when pressed but nothing works. I had to disconnect the A/C lines to remove heater box. would being low on Freon make the system inoperable? I tried to put Freon in but it only took about half a can the lines got frosty but the system didn't work. the switch for air direction doesn't work, fan doesn't work. seems like no power to blower switch. would you know the color code for fan switch wire? thanks, Mike
Oct 23, 2019 at 3:08 AM
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KASEKENNY
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There could be a couple of issues with this so we need to start by checking the pressure in the system because that can cause the compressor to not come one.

So here is a guide that will help with this:

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Once we know what the pressure is we will have a better idea what the issue is.

If the pressure is okay, then we need to double check the connections because that is the next likely cause.

https://www.2carpros.com/articles/replace-heater-core

I am attaching the chart below that will help with telling if the pressure is correct or not.

I suspect this is what we are going to find as the issue so let me know what you find, and we can go from there.

Thanks
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Jan 21, 2022 at 2:21 PM