Weak Chassis AC

A/c is a relatively simple system. There is only one moving part. Unfortunately the whole system is pressurized and you need allot of expensive specialized tools, knowledge and parts to make a repair. Refrigerant is not something to mess with. It can cause allot of health problems. The first thing that you would need to do before putting a wrench to any part of the system is recover the refrigerant.

CVD, if you really don't know about AC systems, do like Doug said and take it to a professional. And, I can recommend a perfect place that fixed ours.

Go to Redlands Performance and RV service in Redlands, CA. They are the best. Do not go to Colton Truck Terminal in Colton, they tried 3 times to play with my AC system charging me each time and no fix.

Redlands Performance and RV Service fixed my AC system the first time and it has been ice cold for 2.5 yrs. now. They are my go-to people and have done other things for me including new hoses and other minor repairs/maintenance. They installed the new air brake system on my new Honda. They have never had to redo anything they have fixed. I'm sure it happens, but they are good and will stand behind their work.

Don't throw money at your AC, get it fixed right.

Good luck,
MM.

doug has it right. the pic you posted shows a hwh hydraulic pump and tank.
it is not even remotely related to a chassis a/s system.
you are about to cause yourself a very expensive problem.
if you dont know this, you should consult someone who does.
information is free, all you have to do is ask.
download a service manual for your chassis a/c system. its available on the internet. sometimes totally free.
chassis air is notorious for not cooling enough. have the pressure checked by a local shop. ask if they are equipped to do the job of repairing the a/c system. truck shops are a good place to call. if they work on rv;'s.
dont proceed if you dont have good information. its very expensive to just throw parts at it.
i dont mean to be preachy, but this could get very pricy.

There is a very good chance that you dumped all of the gas when you checked the compressor oil. I would suggest an AC tech to pump it down to vacate the system and then refill with the R134A. Unless you have a vacuum pump it is not a DIY job.

bounder39zman wrote:
The photo with black tank is hydraulic oil tank for slide-out or leveling jacks or both... not related to a/c system. I agree with other posters....if you are not comfortable with a/c service, take it to a pro. Can be $$$expensive and dangerous if you dont have experience with a/c work.

READ this. You are close to causing an expensive problem. Your lack of knowledge will hurt you. There is NO WAY to check oil level in a AC compressor. Low oil is extremely rare. Even after a massive leak.
IF the compressor is not coming on then the Freon/134a is low. You could have a bad low pressure switch but trying to determine that by buying coolant can get expensive. Get it to a Motorhome experianced Dash AC shop. Doug

The photo with black tank is hydraulic oil tank for slide-out or leveling jacks or both... not related to a/c system. I agree with other posters....if you are not comfortable with a/c service, take it to a pro. Can be $$$expensive and dangerous if you dont have experience with a/c work.

You may have to take it to an A/C shop and have them trouble shoot it before you throw more money at it or damage something. I do all my own repairs, but I know there are some things that should be left to a repair shop, like A/C issues. Make sure you take it to an A/C shop, not a general mechanic.

I am guessing that you have a low pressure switch on your compressor that will not allow it to run when your freon is too low. You might try to jump across the low pressure switch, which looks like the switch right near your fill port, to get the compressor to turn and then see if it will accept a charge from the refill bottle. This may be only a small electrical switch near your compressor with two wires coming out of it. unplugging and shorting the two wires together should allow the compressor to turn, assuming that you have electrical power to the compressor clutch.

Update - I have a compressor problem. I tried recharging the refrigerant. With the engine running and AC on high, the compressor made no sound at all (condenser fans didn’t turn either). No refrigerant was “sucked out” of the refill canister

Where do I look for reasons the compressor won’t run? I’m hoping it’s some sort of electrical problem and not a bad compressor.

I checked the compressor oil. It was at the low end of the dip stick marks, but it wasn’t empty. I don’t see an AC fuse in the fuse box under the dash. I’m guessing it’s controlled by a relay (but don’t know where it is).

Suggestions?

Here is what I’m looking at:

Maybe I’ve been lucky, but I’ve never had to recharge an AC system. I’ll give it a try. I see a number of threads and Youtube’s showing how to add refrigerant to a generic car. Is my Freightliner XC (rear engine, front AC) any different? I looked at the AC condenser and found a hose going to a junction that looks like what the video’s show for the recharge port. Is this the right spot?



A couple questions about what to buy. At Amazon.com, “R134 refrigerant” returns dozens 12 oz canisters. Some with hoses, some without, some with UV dye, some for high mileage vehicles, etc. Anything in particular I need (probably the connection hose and some sort of valve)?

Also, how do I know I need 12 oz? Is that intended to top-off or refill a system?

Thanks,