MILIN1609

Hi,
I have my "AC off" light on, under the volume control buttons.It's the bottom left button. Some members said, when freon is low, automatically that light comes on and dis-engages the AC, so, that there wan't be any burden on the compressor. My question is:
How to add freon? How easy is it?
Thanks a lot.

Baked Benz

pretty simple, go to Walmart and buy a kit and a few cans, read instructions and go.

bamberger_1

Guess it is not that simple. First of all the S-class does not have Freon in the A/C. It is the new stuff R134a. Secondly first you need to find out where the R134a went. If there is a corroded pipe, condensor or evapurator refill does not do any good for long. Thirdly if all the R134a went you also need the lub-oil to be replaced for the compressor.
Best place to get the things done right is either the MB-shop or a certified A/C service.
Remember you own a car to last and treated well, right??

Baked Benz

R134A is freon, just a little more ozone friendly is the claim.The old R12 is not available any more in retail stores anyways.
And its real easy, high side and low side schraders are marked and color coded, its an easy job, certainly worth spending $30 on before taking it any further.

DRTYLNDY

Completely agree. I did it myself a few weeks ago with a R134a & oil recharge can combo from Autozone which costed me about $27 and took me less than 5 minutes. It is very simple and pretty much error proof. Good luck.
Johan

Baked Benz

yeah, i,ve done this many times, yes of course there may be other problems with the system but in my experience A/C repair is on a par with trany repair when you take it in to a shop,i.e. its always a BIG fkn bill.
So try the freon charge, , hell if its just a slow leak ,once in 4 years is not too bad.
One point,dont get too carried away with the oil recharge, this should really be used when installing a new compresor or breaking down/draining the system,a little is ok on a recharge but dont go nuts, the same goes for the recharge on the freon, the gauges on these cheap kits with the color guides are VERY in accurate, my advice is use a little at a time,one 12oz can goes a loooooooooong way,more is not always better,lol.

MILIN1609

Thanks guys,
I tried this route, but still no luck. Here's what I did.Correct and advise, is wrong.
I purchased a R134a refregerant and a gauge. I tried to measure the pressure, but as you said, this cheap gauge is wrong from the word go. It measured extreamly high pressure, even higher that the gauge reads. Not only that, it wan't go back to zero after dis-engageing it. Then I thought, furget about pressure, let's just add the freon. I attached the tube to the low end(small tube)hose. BTW, that's only where it will connect.Screwed the can on the other end. punctured the can and realeased the freon. But, on the the can it says, let the AC run on high. In my S430, it is not engageing at all. How the hell it will flow in the system. Waited for 15 min., but the can was as is. No gas entered in the system. Now, I am really confused. Please help.

Baked Benz

Ok, what happened is you tried to load up with the sysyem on shut down, thats why you got the freaky readings on your gauge, ect, ect, you need to charge while the system is running, then you will be getting somewhere.
So as I never had my systems totally shut down in the safety mode you mention we need to get your compressor running so u can charge the system.I,m pissing in the dark here , but I would dis-connect the battery, wait 5 mins, re connect then try, other than that you could just power the compressor with a live feed I guess. Any one else know how to kick it over.?BY THE WAY, you did check the FUSES right????

MILIN1609

I tried look on the left side box under the hood.There are some fuse that you can see through and figure out, but some are black box looking.I don't know about those.

dexter5

It seems that your system is nearing empty therefore the system shuts down and does not operate the ac compressor.

Proceed at your own risk...

I would take it to an ac shop or a good independent mechanic or dealer, but if you must do this. Then find the receiver drier; usually long cylinder with the ac lines going to it. You will find the pressure sensor there. If your system is nearing empty this sensor does not engage the compressor to prevent damage to your ac system. So you will need to jumped this wire tricking it that there is enough freon in the system. Before you jump this sensor you will need to turn on the ac and to the max. Once you jump this then you will see the compressor clutch engage and then you can recharge. If this works then you were low on freon and might have a leak somewhere.

There might be other sensors that is not working that could be causing your problem. Good luck.

MILIN1609

Thanks for the advise.
I found the receiver drier.It is a part where the high end tube of AC system connects which is right behind the driver side head light. I found two sensors connected it it. Which one should I try?

dexter5

I think there is two on the top correct? I believe it is the one that is not in the middle. Pull out the connector and jump it. I think it might be a three wire connector don't remember..

MILIN1609

I pulled out the sensor which is not in the middle. It has three wire connector.The other one, next to it has two wire connector. The three wire one is little bigger. Now, how to jump it? Do I connect all three wires together in the sensor( the part connected to the wire) or in the sensor plug(the part connected to the drier? I tried to connect either two, with a wire ,but nothing happened? Please help.

dexter5

Was the car (idle) and ac on?
(I'm not sure on this so be careful!!! You might break more...)
you would jump the wires in the plug ( I use a paper clip or wires to jump). Do not jump the sensor ( the part connected to the drier) Try 2 at a time only. If it is correct then the compressor clutch will engage and you can charge the system. If this is not working then please take it to the mechanic or an ac guy. Also have you checked all the fuses..

MILIN1609

Thanks Dexter5 for the guidence.
The car was on idel and AC was not on, because I can't turn it on. The red light(AC off button) is not allowing to engage the AC.
If you can tell me which fuses to check, I will appreciate that.
If this wan't work, I will take to an AC guy.
Thanks anyway.

dexter5

I will look for which fuses. But once you jump the wire try pressing the ac off button.. and put the car a/c temp to low/automatic see if that works. Where are you located?

MILIN1609

I'll try and let you know.I am in Savannah, Ga.

MILIN1609

Hi Dexter5,
Did got any chance to look for the fuses? Plaese, let me know.

Baked Benz

Hi Again, did you try diconnecting the re conn the battery to see iif that resets it??If it comes to it I,m sure most shops would know how to re charge it for you, just let them know you just want a re- charge and not a system re placement.

dexter5

I will let you know today; I'm getting the diagram soon.

MILIN1609

Just reminding!!!

dexter5

I will pm the pdf file to you. Cannot pm the file. So pm me your email address and I will send the file that way.

Baked Benz

Damn this is an Odyssey, lol.
God forbid they made it easy and just had a Re-Set button.

http://www.mercedesshop.com/shopforu...ad.php3?t=6707

MILIN1609

Finally, I had to take it to the dealership. Off course, it was very low on the freon. It was below its limit, so the system shuts down the compressor. Our assumption was right. But we could not figured out, how to make the system to accept the freon from the can!! Any way, we learn from the failures too. Was not that bad. Cost me $171 . But I got Lots of knowledge through this thread. I thanks who participated.