2016 LC A/C Issues

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Joined
Mar 16, 2022
Messages
12
Location
Wisconsin
Long time lurker, former 100 Series owner, now driving 2016 LC purchased CPO in 2017, before they were gold-plated.

Drove from Wisconsin to Arizona this winter and first indication that something was amiss is that the cold box made our food warm rather than cold, but we checked the OM and it said that the cold box might not work at ambient temps below 32 degrees. But on warm days in AZ it became apparent that the air conditioning was not working, which was not the end of the world since daytime temps were only in the 70s.

We are back in WI now and I have begun diagnosis, without the benefit of a service manual, other than the nice paper ones that I still have from the 100 series. I did find a MUD posting with the procedure to check the compressor clutch on the 200 series which I have done by measuring the resistance of the clutch coil and energizing the clutch direct from the battery--resistance quoted in the service manual excerpt is 65-125 ohms, I measured 3.5 ohms with two different meters. When I energized the clutch direct from the battery it seemed anemic at best--normally there is a crisp actuation audible from inside the vehicle, at least at idle. So I am suspicious of the clutch.

But I also need to buy a R134a gageset to measure the refrigerant pressure--all my A/C stuff is for R12 used on an old Mercedes turbodiesel that I still chug around in during the summer. I found the suction gage connection near the brake master cylinder but don't know what the pressure should be--could someone please advise? I am assuming that there is a pressure lockout switch that prevents the clutch from energizing if there is insufficient refrigerant in the system.

I am also wondering if the clutch can be replaced in situ if that is the problem--I looked at the procedure for the 100 series and it required a couple special tools which I of course do not have. So I will likely find a dealer or A/C shop to fix it, but a bit of knowledge and information on the front end always helps. I am 70+ years old and crawling around under vehicles is not as appealing as it once seemed.

Thanks for any useful information.
 
Long time lurker, former 100 Series owner, now driving 2016 LC purchased CPO in 2017, before they were gold-plated.

Drove from Wisconsin to Arizona this winter and first indication that something was amiss is that the cold box made our food warm rather than cold, but we checked the OM and it said that the cold box might not work at ambient temps below 32 degrees. But on warm days in AZ it became apparent that the air conditioning was not working, which was not the end of the world since daytime temps were only in the 70s.

We are back in WI now and I have begun diagnosis, without the benefit of a service manual, other than the nice paper ones that I still have from the 100 series. I did find a MUD posting with the procedure to check the compressor clutch on the 200 series which I have done by measuring the resistance of the clutch coil and energizing the clutch direct from the battery--resistance quoted in the service manual excerpt is 65-125 ohms, I measured 3.5 ohms with two different meters. When I energized the clutch direct from the battery it seemed anemic at best--normally there is a crisp actuation audible from inside the vehicle, at least at idle. So I am suspicious of the clutch.

But I also need to buy a R134a gageset to measure the refrigerant pressure--all my A/C stuff is for R12 used on an old Mercedes turbodiesel that I still chug around in during the summer. I found the suction gage connection near the brake master cylinder but don't know what the pressure should be--could someone please advise? I am assuming that there is a pressure lockout switch that prevents the clutch from energizing if there is insufficient refrigerant in the system.

I am also wondering if the clutch can be replaced in situ if that is the problem--I looked at the procedure for the 100 series and it required a couple special tools which I of course do not have. So I will likely find a dealer or A/C shop to fix it, but a bit of knowledge and information on the front end always helps. I am 70+ years old and crawling around under vehicles is not as appealing as it once seemed.

Thanks for any useful information.
 
Long time lurker, former 100 Series owner, now driving 2016 LC purchased CPO in 2017, before they were gold-plated.

Drove from Wisconsin to Arizona this winter and first indication that something was amiss is that the cold box made our food warm rather than cold, but we checked the OM and it said that the cold box might not work at ambient temps below 32 degrees. But on warm days in AZ it became apparent that the air conditioning was not working, which was not the end of the world since daytime temps were only in the 70s.

We are back in WI now and I have begun diagnosis, without the benefit of a service manual, other than the nice paper ones that I still have from the 100 series. I did find a MUD posting with the procedure to check the compressor clutch on the 200 series which I have done by measuring the resistance of the clutch coil and energizing the clutch direct from the battery--resistance quoted in the service manual excerpt is 65-125 ohms, I measured 3.5 ohms with two different meters. When I energized the clutch direct from the battery it seemed anemic at best--normally there is a crisp actuation audible from inside the vehicle, at least at idle. So I am suspicious of the clutch.

But I also need to buy a R134a gageset to measure the refrigerant pressure--all my A/C stuff is for R12 used on an old Mercedes turbodiesel that I still chug around in during the summer. I found the suction gage connection near the brake master cylinder but don't know what the pressure should be--could someone please advise? I am assuming that there is a pressure lockout switch that prevents the clutch from energizing if there is insufficient refrigerant in the system.

I am also wondering if the clutch can be replaced in situ if that is the problem--I looked at the procedure for the 100 series and it required a couple special tools which I of course do not have. So I will likely find a dealer or A/C shop to fix it, but a bit of knowledge and information on the front end always helps. I am 70+ years old and crawling around under vehicles is not as appealing as it once seemed.

Thanks for any useful information.
Looks like the earlier attempted reply did not make it through. Computers are tough for old guys with fat fingers.

Just wanted to advise of the solution--clutch itself was fine, no refrigerant leaks, there is a relay in the under-hood fuse/relay compartment identified as MGT_CL that controls current flow to the clutch, Part No. 90987-02028 for the '016 model. Relay had failed. At least I figured it out before taking it to the dealer.
 

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