A/C switch just blinks when pressed (blows warm)
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GL63
A/C switch just blinks when pressed (blows warm)
This started in the heat of summer last week. Dealer said $260 to read fault codes as first step.
I read on this forum R134 is probably low so (WRONG)….after I connected the can from autozone it immediately read HIGH with car running ac on max fan high pressure.
what could it be?
I read on this forum R134 is probably low so (WRONG)….after I connected the can from autozone it immediately read HIGH with car running ac on max fan high pressure.
what could it be?
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Joined: May 2021
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
Have you scanned the vehicle for error codes?
A good bidirectional scanner can be had $200, or less via AliExpress: Launch Creader Elite v2 for Benz.
With an Mb-aware scanner, you can monitor live data of the AC system, and find out yourself if the compressor is actuated, current refrigerant pressure, evaporator temperature, etc
A good bidirectional scanner can be had $200, or less via AliExpress: Launch Creader Elite v2 for Benz.
With an Mb-aware scanner, you can monitor live data of the AC system, and find out yourself if the compressor is actuated, current refrigerant pressure, evaporator temperature, etc
Thread Starter
Junior Member
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GL63
I’ll add a little follow up. When the car is shut off and restarted the AC works…..but only for a few minutes which is indicative that the system is shutting down the AC compressor in order to protect it. When I said the low side AC pressure was high I mean “in the red” on the “top up can gauge”. By top up can I mean the $30 can you buy at Autozone. Typically a low system will read yellow (low pressure) and as you add a bit it will goto that green indicator area on the gauge. What I saw was an immediate HIGH pressure issue in the system and I probably should not have but went ahead and added the contents of my small can to the system hoping the high reading was “incorrect”. After adding the can of r134 no change the system turns on AC works but after a few minutes drops out and trying to activate the AC or Max AC switch the led indicator simply blinks 3 times and you have to restart the engine upon Which you’ll get three minutes of AC until again the process repeats (system shuts down the compressor). Hopefully someone who has seen this before can chime in. Wondering if it’s a block evaporator etc….car has 90000 original miles on a 2014 model year.
MBWorld Fanatic!
Joined: May 2021
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
I’ll add a little follow up. When the car is shut off and restarted the AC works…..but only for a few minutes which is indicative that the system is shutting down the AC compressor in order to protect it. When I said the low side AC pressure was high I mean “in the red” on the “top up can gauge”. By top up can I mean the $30 can you buy at Autozone. Typically a low system will read yellow (low pressure) and as you add a bit it will goto that green indicator area on the gauge. What I saw was an immediate HIGH pressure issue in the system and I probably should not have but went ahead and added the contents of my small can to the system hoping the high reading was “incorrect”. After adding the can of r134 no change the system turns on AC works but after a few minutes drops out and trying to activate the AC or Max AC switch the led indicator simply blinks 3 times and you have to restart the engine upon Which you’ll get three minutes of AC until again the process repeats (system shuts down the compressor). Hopefully someone who has seen this before can chime in. Wondering if it’s a block evaporator etc….car has 90000 original miles on a 2014 model year.
Here is my experience with the 2014 E350 (100K miles this month). Original refrigerant charge, and it still cools like freezer. Only issue in 10 years was the magnetic clutch, and I replaced w/o disconnecting the compressor, i.e. in-place.
On the 2012 ML350, I changed the electronic control valve since it seemed to be sticky, and the Schrader valve (missing refrigerant when evacuated). So far cooling great again.
The other two MB are using their original compressors, 2008 E350 @150K+ miles, and 2015 ML 350 @96K miles.
Advice:
First, an important notice, do NOT use those cans on these AC systems because these systems should NEVER be topped up unless you know EXACTLY, by weight, how much refrigerant is missing. These are variable displacement compressors that can change the delivered high pressure regardless of the amount of refrigerant in the system. Unlike fixed displacement compressor, they adjust as you are charging; therefore, you do not know if you need more refrigerant or NOT. SUMMARY: be extremely careful.
Next?
Do you have a trouble shooting chart for these kind of compressors, so that you can diagnose the system using the set of pressure gauges. For example,
https://www.densoautoparts.com/troub...ts-compressor/
https://www.densoautoparts.com/refer...oubleshooting/
More important, careful starting a parts canon since you can get into spending $$$ and still have an AC problem.
Last edited by JCM_MB; Aug 29, 2024 at 11:32 AM.
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10 C six trizzle
Using autozone can with colors isn't going to tell you much at all. You need to know what your pressures are reading to give you any useful input. Technically even with low side reading too high the system could still be too low on refrigerant. Although that is unlikely to be your issue. There is an actual value that will give a reason for compressor shutoff but you need a good scan tool to tell you. Between that and putting some gauges on it, with out having a magic wand this simply cannot be fixed online.
Thread Starter
Junior Member
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GL63
Using autozone can with colors isn't going to tell you much at all. You need to know what your pressures are reading to give you any useful input. Technically even with low side reading too high the system could still be too low on refrigerant. Although that is unlikely to be your issue. There is an actual value that will give a reason for compressor shutoff but you need a good scan tool to tell you. Between that and putting some gauges on it, with out having a magic wand this simply cannot be fixed online.
wrong. Those gauges are a very good indicator of what’s going on (on the low side). I installed for sake of argument my low and high side gauge set when I got home from travel (having used a small
gauge) and it reads exact same. Low side is high and high side is reading low. Thanks to the fellow who posted a chart on troubleshooting. I’ll follow that.
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MBWorld Fanatic!
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
As long as you do not use those can to charge by pressures, you will be fine. Recall you need to be able to know how much refrigerant is IN by weight. Pressures mean nothing about refrigerant quantity unless is ZERO
Here is another chart, more visual and compact
https://nissens.com/Admin/Public/Dow...134A+-+ENG.pdf
Here is another chart, more visual and compact
https://nissens.com/Admin/Public/Dow...134A+-+ENG.pdf
Last edited by JCM_MB; Sep 2, 2024 at 05:12 PM.
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MBWorld Fanatic!
Joined: Oct 2007
Posts: 2,298
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From: Texas
10 C six trizzle
wrong. Those gauges are a very good indicator of what’s going on (on the low side). I installed for sake of argument my low and high side gauge set when I got home from travel (having used a small
gauge) and it reads exact same. Low side is high and high side is reading low. Thanks to the fellow who posted a chart on troubleshooting. I’ll follow that.
gauge) and it reads exact same. Low side is high and high side is reading low. Thanks to the fellow who posted a chart on troubleshooting. I’ll follow that.
Thread Starter
Junior Member
Joined: Mar 2023
Posts: 41
Likes: 8
GL63
Initial pressure immediately behaves abnormal out of range on high side only with an operational compressor upon which after a few minutes the compressors shuts down and system pressures recorded are out of range on high side as well as low side.
the troubleshooting chart available online indicates potential compressor failure or expansion valve. I’ll replace it evacuate the system, run vaccum and re charge it. Wasn’t needing all the information. Take care
the troubleshooting chart available online indicates potential compressor failure or expansion valve. I’ll replace it evacuate the system, run vaccum and re charge it. Wasn’t needing all the information. Take care
MBWorld Fanatic!
Joined: May 2021
Posts: 2,524
Likes: 2,041
From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
Initial pressure immediately behaves abnormal out of range on high side only with an operational compressor upon which after a few minutes the compressors shuts down and system pressures recorded are out of range on high side as well as low side.
the troubleshooting chart available online indicates potential compressor failure or expansion valve. I’ll replace it evacuate the system, run vaccum and re charge it. Wasn’t needing all the information. Take care
the troubleshooting chart available online indicates potential compressor failure or expansion valve. I’ll replace it evacuate the system, run vaccum and re charge it. Wasn’t needing all the information. Take care
Thread Starter
Junior Member
Joined: Mar 2023
Posts: 41
Likes: 8
GL63
Just a heads up the issue fixed itself. I have no clue how but all summer the AC (this year) no issues whatsoever. Last year intermittent (not that AC starts to depreciate or decline in performance but rather) would not work at all.
it remains unexplained and no I didn’t goto a shop,
It’s possible there was some blockage potentially and somehow it’s cleared itself. I may go ahead and hookup my gauges and see what pressures I am seeing.Thanks all!
it remains unexplained and no I didn’t goto a shop,
It’s possible there was some blockage potentially and somehow it’s cleared itself. I may go ahead and hookup my gauges and see what pressures I am seeing.Thanks all!
