AC flakes in car line

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camino70

camino70

10 Year
Joined
Jul 1, 2015
Threads
51
Messages
1,344
Location
Canton, GA
I don’t normally pick the kids up in car line, but when I do twenty minutes idling, the ac light starts flashing and stops operating.

For some reason i thought maybe flakey relay, which i replaced with new oem.

The ac’s been fine driving for hours at a time, but picked kids up in car line yesterday. Sure enough twenty minutes in = flakey

It wont work again till it all cools down.

Three hours into drive now, everything operational
 
Did the relay actually test bad or did you just change it preemptively?
 
Do you have any mods? Armor, underbody armor? Engine covers?
 
camino70 said:
Negative
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Gotcha. I've idled for hours in the hot desert off-road crawling with friends and the one thing that the 200-series is hugely robust with is cooling robustness. These things were designed to hold up in the harsh Middle East climates. Never had a problem (unlike buddies F150 Raptors).

Get an OBD-II reader that can report the engine coolant temp.

Has the vehicle ever been in an accident? Does it have all the OEM gaskets and shrouding in place?

Might want to check the cooling system. How many miles do you have and has the water pump ever been changed? Could also be things like the cooling fan clutch, pressure cap, A/C condenser and radiator for contaminants/bent fins/mud.
 
No prior accidents, replaced radiator not too long ago (foam in place) coolant replaced somewhat frequently.
No fins look messed up, dirty

Carpool lane today, coolant temp went from 85 ->90. Ac didn’t flake out today.
 
He, Any update? I have a similar problem
 
dubaicruiser said:
He, Any update? I have a similar problem
Click to expand...
Sorry dubai, I missed this message. No real updates I think I was lucky through the summer and didn't really idle anywhere. Now that I'm using the ac again this year I have the problem exhibiting much quicker. I removed the condenser fan, it spun, but with no force, I think simply from the suction of the radiator fan. Direct 12v to it and it doesn't spin. I replaced it and went to test after a short drive, again, not much force. I'm not getting 12v to the connector, no blown fuses, good ground and I'm currently troubleshooting.
 
I swapped the CDS relay with the fog lamp relay, the fog lamps work with both relays. From condenser fan connector I reconfirmed ground connectivity successfully. I also successfully tested connectivity from the 12v connector to the top spade of the relay, pin 87. I have two 12V at the relay, pins 30 and 86. I have no ground on pin 85 from ecu. The fan runs great when pin 87 gets jumpered to 12v.
Where am I looking from ecu to pin 85?
Thoughts on short term jumper, run all the time with truck on through 30/87 jumper or possibly from MG CLT so it's on when the AC is on?
 
About 60F out this morning. I hooked techstream up, about 10 minutes in I get the AC On/Off switching. I didn't see any codes thrown and all I really noticed was the Estimated Temp Rear = -613.12.
Techstream AC

Techstream AC

  • Media owner camino70
  • Date added
 
GrouchyTech said:
Do you have refrigerant?
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I thought I did. The cheap ac gauge I had said I was in range and I need to relearn what to expect to see in the sight glass by the highside valve. I took it to a shop yesterday and they said I had 1.5lbs and the system called for 2.5lbs. I guess I'll be searching for a leak somewhere now. I still haven't figured out the condenser fan
 
camino70 said:
I thought I did. The cheap ac gauge I had said I was in range and I need to relearn what to expect to see in the sight glass by the highside valve. I took it to a shop yesterday and they said I had 1.5lbs and the system called for 2.5lbs. I guess I'll be searching for a leak somewhere now. I still haven't figured out the condenser fan
Click to expand...
If you have much corrosion a very common refrigerant leak source is where the lines go through the floor into the rear aircon unit. Above the resonator on the exhaust pipe you’ll see some AC lines against the floor, and there is a junction on each where you can disconnect the line.. that junction block is prone to corrosion and leaking.

Without corrosion.. I’d take a good look at the condenser for rock strikes. We don’t have very frequent leak spots other than the above.
 
bloc said:
If you have much corrosion a very common refrigerant leak source is where the lines go through the floor into the rear aircon unit. Above the resonator on the exhaust pipe you’ll see some AC lines against the floor, and there is a junction on each where you can disconnect the line.. that junction block is prone to corrosion and leaking.

Without corrosion.. I’d take a good look at the condenser for rock strikes. We don’t have very frequent leak spots other than the above.
Click to expand...
Luckily a southeast truck, little to no corrosion, but I’ll check all you listed. Thanks
 
camino70 said:
I thought I did. The cheap ac gauge I had said I was in range and I need to relearn what to expect to see in the sight glass by the highside valve. I took it to a shop yesterday and they said I had 1.5lbs and the system called for 2.5lbs. I guess I'll be searching for a leak somewhere now. I still haven't figured out the condenser fan
Click to expand...

Just glanced at this again-- When the A/C compressor is locked-out like you describe (flashing A/C light), there will be no command sent for the condenser fan to operate.
 
Thanks guys. Even when the AC is operating/engaged, I never see voltage going to the condenser fan.
Unfortunately I got the flicker while driving in some slight stop and go traffic this afternoon. My first high level look over with the UV flashlight wasn't fruitful. I did see dye in the sight glass, no where else, but it was just a quick overview.
Condenser looks ok from my vantage point.
 
camino70 said:
Thanks guys. Even when the AC is operating/engaged, I never see voltage going to the condenser fan.
Unfortunately I got the flicker while driving in some slight stop and go traffic this afternoon. My first high level look over with the UV flashlight wasn't fruitful. I did see dye in the sight glass, no where else, but it was just a quick overview.
Condenser looks ok from my vantage point.
Click to expand...
Wait, so the condenser fan NEVER works…?

If the fan never gets voltage and never works, and if the fan also tests OK (just apply 12V to the two terminals) you could have a failed A/C amplifier, and the signal for the condenser fan is not sent. If the condenser fan can't run it's not much concern while driving, but when parked (or picking the kiddo up) the pressure will become high enough for the compressor to lock-out.

BUT.. I'm reading your data list and the regular pressure is 60 PSI, which wouldn't cause this problem. It may be helpful to graph a few things to see what changes when the A/C locks-out.

This definitely seems related to airflow over the condenser.
 
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