It only blows hot air, I replaced fuse 16

TMCINTOSH11

MEMBER
2002 DODGE RAM
4.7L
V8
4WD
AUTOMATIC
280,230 MILES

I been tinkering with it off and on since it only blows hot air, I replaced fuse 16 for the A/C clutch since it was blown but it made no difference. I checked all other fuses and the wiring seems fine from what I can tell, I also noticed the compressor clutch doesn't engage at all, not even try. I tried checking the system pressure while running with the A/C turned all the way up and it gave no reading, the needle didn't budge. I'm not really knowledgeable on A/C systems so does this mean it needs freon? Or will it only give an accurate reading if the clutch is engaged? Also it makes no noises, no clicking, no humming, no grinding or anything.

Monday, July 19th, 2021 AT 7:52 PM

3 Replies

KASEKENNY

MECHANIC
18,907 POSTS

Okay. This could be an electrical issue or it could be a Freon issue, or it could be a component issue like the compressor.

We need to start with checking the pressure with a gauge set. Here is a guide that will help with this process plus a video of the same info if you prefer that:

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

https://youtu.be/4EqdrBVb0sY

You said the gauge did not move so was that a gauge on one of those cans of Freon? If so, they unfortunately will not tell us what is going on with the system. We need to know the high and low side to tell if the system is empty.

Here is a guide that will help with what I am talking about:

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Once we know what the pressure is, we will know what direction to go. I also attached a chart below on what pressure should be based on ambient temperature.

Please run through this and let us know what you find with this and we can take the next step. Thanks

Image (Click to make bigger)

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Monday, July 19th, 2021 AT 7:58 PM

TMCINTOSH11

MEMBER
176 POSTS

Thanks Kenny,

Yeah, I forgot to mention it was a gauge from a can of A/C pro, when the gauge wasn't responsive I decided not to add any at the moment because I didn't know if that was accurate or not. I'll try and pick up a better better testing gauge from maybe AutoZone. Once I have the gauge connected do I run the engine with the A/C on full? Thanks!

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Tuesday, July 20th, 2021 AT 4:08 AM

KASEKENNY

MECHANIC
18,907 POSTS

You are welcome. You are correct that they are not accurate and break easily. However, if it did not move at all, I suspect the system is empty.

It is always a good idea to check with a gauge set so let us know what you find and we can go from there. Thanks

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Tuesday, July 20th, 2021 AT 7:57 PM