Ac Light Blinking / Not Working

[DANDAGS4MAN]

I just got my alternator changed on my GS400 - Solved all power issues I was having. However, when I got the car back I used the AUTO function on the AC/HEAT to maintaine a certin temp. When doing so the AC light just flashes and no cold air comes out. I've checked to ensure that all pully wheeles where turning and there wasn't to much slack on the belt - All checked out fine. The AC worked before the alternator was replaced ...... Any ideas

[sakataj]

is the compressor coming on when you hit the ac button? you should hear/feel it! could have a bad low or high pressure switch, maybe they didnt plug one of the ac plugs back in........or what im thinking is you might be low on freon! but start with the basics, find out if the compressor is kicking on and get back to me.........i manage a heating/air supply house in memphis and although we dont specialize in cars we do dabble in automotive a/c!

brian

[DANDAGS4MAN]

Thanks for the reply!

Checked it out here is what i found:

-Looked at alternator and there was a unconnected wire co I re-connected that.

-Started the car and still nothing.

-Listened for the compressor sounds like it comes on for a second, fender fan at the front starts then stops. Cold air begins to come out when first turned on.

-Checked the RPM when turning the AC on reves higher when the AC is firsttuned on.

[GuyTelefunken]

You can perform the onboard diagnosis located Here and see if you come up with any codes. It probably would be a good idea to go back to the place that changed your alternator and ask them to make sure they didn't disturb, disconnect, etc. something that caused this.

[sakataj]

hey GuyTelefunken,

wil this work on the ml also? i have a servo/blend door/ something out and for some reason only my drivers side is consistentatly warm, some days my passenger floor blows cold!

brian

[GuyTelefunken]

For some reason, the procedure for the non Mark Levinson is all I have in my info.

[sakataj]

:cries: :cries: well crap...............thansk anyway

brian

[punash007]

:cries::cries: well crap...............thansk anyway

brian

Please check your AC relay,MG CLT or Mag Clutch Relay first to see if that is the problem, if not it could be your AC speed sensor. The ac speed sensor sees a difference between the engine speed and the actual compressor speed if there is a difference of 10% or more it shuts off and flashes the AC light. It could also be that the belt is not tight enough. Good luck.

[punash007]

I just got my alternator changed on my GS400 - Solved all power issues I was having. However, when I got the car back I used the AUTO function on the AC/HEAT to maintaine a certin temp. When doing so the AC light just flashes and no cold air comes out. I've checked to ensure that all pully wheeles where turning and there wasn't to much slack on the belt - All checked out fine. The AC worked before the alternator was replaced ...... Any ideas

Did you get your AC issue fix and what was wrong?

[sakataj]

no not exactly, the servo actually is a heat problem doesn't do it like that when its ac only but i think i have a bad expansion valve but now im not sure, since last week its been acting right!

"i will welcome myself back to the forum as im,woo hooooooooo, finally unsuspended! hahaha!"

brian

[Mohamed1985]

I have the same problem happened with me, I found that the compressor sensor is faulty, now 2 solutions either to change the compressor as sensor cannot be repaired which will cost more money, or bypass the compressor sensor by small copper wire and it will work perfect, I chose to bypass the compressor sensor and it worked fine with me so far

[lexusgs30000]

@Mohamed1985 you how can i find a video on how to by pass the compressor censor?