AC Clutch Relay (1 Viewer)

[zeebrax]

Hey on my 13 LC with 136k the AC just stopped working. Noticing the clutch on the AC compressor isn’t engaging or trying for that matter. I’m starting simple and wondering if the relay is bad. Which one would that be or any other fuse involved that I should take a gander at? O also just had the system charged and dyed too.

Thanks guys. I looked and couldn’t find anything on it. Maybe I did a poopy search. Sorry if it’s been covered.

 

[bloc]

It is called the “MG CLT” relay, and I’m not sure but believe it is in the under hood relay/fuse box.

There is also a sensor in the compressor connected to the AC amplifier called “lock sensor” which I assume provides feedback about whether the mag clutch is working or not.

If you have access to techstream it would be interesting to see the codes that are present in the hvac system.

 

[zeebrax]

It is called the “MG CLT” relay, and I’m not sure but believe it is in the under hood relay/fuse box.

There is also a sensor in the compressor connected to tbe AC amplifier called “lock sensor” which I assume provides feedback about whether the mag clutch is working or not.

If you have access to techstream it would be interesting to see the codes that are present in the hvac system.

I’ll fire up Techstream to see what codes are thrown and report back.

 

[kcjaz]

I assume you checked the freon pressure? I know you said you just had it charged but still put gauges on it. I ask because one day my AC clutch stopped working and I spent a day trouble shooting it testing relays, looking for fuses, jumper wiring it to make it engage just to eventually realize I had a leak in the condenser and it was the AC low pressure preventing the clutch from engaging.

 

[TeCKis300]

I assume you checked the freon pressure? I know you said you just had it charged but still put gauges on it. I ask because one day my AC clutch stopped working and I spent a day trouble shooting it testing relays, looking for fuses, jumper wiring it to make it engage just to eventually realize I had a leak in the condenser and it was the AC low pressure preventing the clutch from engaging.

Good info. Curious where the leak was?

I seem to recall others may have had a leak at o-rings near the evaporator and another on a line near the rear of the chassis that is suspectable to corrosion? Wonder if there's anything that can be identified as common longer term.

 

[kcjaz]

Good info. Curious where the leak was?

I seem to recall others may have had a leak at o-rings near the evaporator and another on a line near the rear of the chassis that is suspectable to corrosion? Wonder if there's anything that can be identified as common longer term.

It was a pin hole right in the front middle.

 

[016LC]

I had to replace this relay on my 2016 LC. You will find that it is inordinately expensive compared to the other Denso relays next to it that appear identical in form and function. The only reason I could come up with is that maybe the contacts are silver plated--they do carry quite a bit of current for the clutch coil and cycle constantly.

Having an inquiring mind, I disassembled the failed relay and found that the coil was still pulling the contacts together, but a continuity tester connected across the contact terminals showed an open circuit. So the contacts had failed.

 

[zeebrax]

It is called the “MG CLT” relay, and I’m not sure but believe it is in the under hood relay/fuse box.

There is also a sensor in the compressor connected to the AC amplifier called “lock sensor” which I assume provides feedback about whether the mag clutch is working or not.

If you have access to techstream it would be interesting to see the codes that are present in the hvac system.

Well I hooked up TS and I’m seeing a B1423 “Open in Pressure Sensor Circuit/Abnormal Refrigerant Pressure”

Thoughts?

 

[zeebrax]

I assume you checked the freon pressure? I know you said you just had it charged but still put gauges on it. I ask because one day my AC clutch stopped working and I spent a day trouble shooting it testing relays, looking for fuses, jumper wiring it to make it engage just to eventually realize I had a leak in the condenser and it was the AC low pressure preventing the clutch from engaging.

Did you get the B1423 code? Because that’s what I’m getting.

 

[kcjaz]

Did you get the B1423 code? Because that’s what I’m getting.

I don’t recall but I think there was a code related to low pressure protection of the compressor. Guages told me pressure was low and then I put a small can of Freon in and it ran. Took it to a shop and then found the pin hole leak. Replaced the condenser and then all
Good.