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Attention Lou P. A/c blows cold then goes hot. New LF, trial…

Attention Lou P. A/c blows...
Attention Lou P. A/c blows cold then goes hot. New LF SAM, trial fitted PBU. Removed evap temp sensor, readings are good according to SDS. Could it be aftermarket compressor?
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3/12/2018
Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 5,730
Experience: 20 years Master Certified excellent fix rate and have access to factory wiring, and instructions.
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Hello my name is***** am going over your request now and will reply back soon with some info OR a few questions that would help me better determine how to help you. Keep in mind I have no idea of your technical ability or what you do and do not already know. So the more info you can tell me the better. I have been on the site for almost ten years and have oustanding 5 star ratings so trust that I will do everything I can to get you taken care of, Lou
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What are you calling the PBU??also thanks for requesting me :)
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Also may i have the vin please
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Customer reply replied 1 month ago
This is from the previous convo you and I started. The PBU is the push button unit for ac
Customer reply replied 1 month ago
WDBNG75J82A284730
Ok lol we call it the AAC automatic climate control. Just making sure. So when ac goes warm what does the sds actual value say for the compressor? And or pressures?
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Currently commuting ill respond more in a few
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Do you have pressure gauges hooked up?
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Customer reply replied 1 month ago
I’ll hook up. But not I’ve lost voltage to my compressor. It was 9.6 now I have nothing
what are the readings with the sds and pressure values ?
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Do you have teamviewer?
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Customer reply replied 1 month ago
Right now, my ac panel (ac light off) is on, will now allow me to press it to turn compressor back on.
Customer reply replied 1 month ago
What is team view? Don’t think I have that
Customer reply replied 1 month ago
Low side pressure is about 68 high is about 75 with no compressor on
Customer reply replied 1 month ago
I’m noticing my fan is not coming on. The engine fan
Customer reply replied 1 month ago
Through left front sam I’m able to actuate compressor and my pressures change. Unable to actuate through ac unit.

ok, so one thing i forgot is when the sds is hooked up you cannot work the ac panel, it wont operate properly from what i remember,

there should be an actuvation test to check cooling and heating,

and yes the fan should be coming on that would be my next question.

so lets activate through the sam, and see what the ac pressure get up to with gauges.

did you ever recharge the ac?

it should have set a low pressure code already if it was low.

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Customer reply replied 1 month ago
Absolutely no codes. The pressures on low side was around 60-65 and high was 150 ish. I didn’t write them down so I’ll have to reconnect and re check. But I disconnected from compressor, ohmed connector to ground, found .347mohms according to SDS, it’s stating compressor is faulty. I performed the self test through ads and got these results

ok, so either you are low on freon or the compressor cannot build pressure.

are you telling me pressures from actual gauges or the sds.

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Customer reply replied 1 month ago
High was 100-110. It only actuated for 10 secs
Customer reply replied 1 month ago
An actual gauge.
Customer reply replied 1 month ago
If the compressor is not building pressure will it eventually shut everything else down? Why would I lose power at it?

ok, then yep either low freon or bad compressor.

especially if you are actuating the compressor and now it has power.

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Customer reply replied 1 month ago
Ok. Well it’s charged with 2.17 pounds. So there is enough Freon. Looks like this new compressor is bad
Customer reply replied 1 month ago
I didn’t know that a bad compressor would cause the request to turn it on to go away. So that’s what was confusing me. I thought it should have voltage regardless.
Customer reply replied 1 month ago
Plus it’s an aftermarket compressor so it could be an incorrect compressor

ok give me a moment.,

sorry for my delay i got pulled away

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can you tell me if your compressor has a clutch on the front ?

or show me a picture of the face of the compressor pulley

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ok your compressor is a swash plate design, you should not have a on off clutch style.

the compressor is variable. so you can get different voltages based upon demand.

so it looks like the new compressor might be bad or not correct.

i can tell you i have never had luck with aftermarket compressors, alternators,starters. blower regulators. for some reason they just dont work.

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Customer reply replied 1 month ago
Thanks. We’ll see if that gets it

ok let me know.

Lou

Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 5,730
Experience: 20 years Master Certified excellent fix rate and have access to factory wiring, and instructions.
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Lou P. master tech
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