Just picked up immaculate '13 LX570 rear A/C not cold enough...intermittent driver footwell hiss (2 Viewers)

[MrX]

Hey guys! Glad to join this group. I picked up a sweeeeet LX, absolutely immaculate. 9.5 out of 10 condition. 100k miles, everything serviced at Lexus. Every single fluid has been changed, etc. It looks and drives like it's brand new. Will post some pics soon! I've owned an LS430 before so I know how good the high end Lexus cars and trucks are.

My question/issue is exactly what I said lol. The rear A/C doesn't get very cold, but the front is fine. I tried a search but couldn't find anything. The Lexus service advisor I called said it's all one system but I'm not sure if she's correct as there is an Acadia and Tahoe in my family where the A/C to the rear is separate, lol they've both had work.

A tad disappointed but hey it's not brand new and I stole it pricewise. There is an intermittent hiss in the driver footwell which I'm pretty sure is A/C related. It's not obtrusive but you hear it. The hiss lasts a few seconds then goes away. It does not bother me, but if it's part of the issue yes I want to fix it.

I'm not a mechanic but I do know a good amount about cars. I'm guessing the truck needs a recharge? Maybe there's a small leak? If it is one system as Lexus said why would the front be fine but not the rear? Since these are tank trucks made for easy service I am not taking it to any dealer lol, maybe the Mr. Cool down the street?

Has anyone experienced this?

Any help would be appreciated! I keep trying to find anything semi popular online about LX570/LC with air conditioning problems but not much turns up (because...things don't break on these really) so I'm hopeful this is an easy fix. I can't describe in words how immaculate this truck is and how much I love it.

Thanks in advance!

 

[bloc]

Below the cup holders for the third row you will see small round module with an electrical component visible.. make sure those are clean. They are the sensors for the rear AC.

Also is the hiss tied to brake application? Our brake boosters are electric with a pump that builds pressure in a hydraulic accumulator each time you hit the brakes, or if the vehicle sits for a while without running. Driver footwell is exactly where you will hear the sound. Could be the cause.

 

[MrX]

Below the cup holders for the third row you will see small round module with an electrical component visible.. make sure those are clean. They are the sensors for the rear AC.

Also is the hiss tied to brake application? Our brake boosters are electric with a pump that builds pressure in a hydraulic accumulator each time you hit the brakes, or if the vehicle sits for a while without running. Driver footwell is exactly where you will hear the sound. Could be the cause.

I will check it, but it wasn't blowing cold even when I turned everything on to max a/c, lowest temp setting.

I don't think it is the brakes either because it stops when you turn all the climate control off.

I'm thinking there's a leak, or at least I hope it's as easy as that or a recharge. Just my luck to buy the most reliable vehicle on the planet and get stuck with a huge a/c bill right away, lol. But hey I got a 2013 100k LX with every single option for $33,500, that, other than this, might as well be a brand new truck.

 

[bloc]

Front and rear AC systems (and the coolbox) use the same refrigerant so it is unlikely to be low if the front system works.

 

[1world1love]

I will check it, but it wasn't blowing cold even when I turned everything on to max a/c, lowest temp setting.

I don't think it is the brakes either because it stops when you turn all the climate control off.

I'm thinking there's a leak, or at least I hope it's as easy as that or a recharge. Just my luck to buy the most reliable vehicle on the planet and get stuck with a huge a/c bill right away, lol. But hey I got a 2013 100k LX with every single option for $33,500, that, other than this, might as well be a brand new truck.

Is it not blowing cold, as in blowing ambient air temp, or is it just not getting as cold as the front?

 

[MrX]

Is it not blowing cold, as in blowing ambient air temp, or is it just not getting as cold as the front?

It's not warm air but definitely not cold, I feel like a small percentage of it feels air conditioned. Not as cold as front. It will be hot when it gets hot outside here, though.

 

[MrX]

It's not warm air but definitely not cold, I feel like a small percentage of it feels air conditioned. Not as cold as front. It will be hot when it gets hot outside here, though.

As in, hot inside the truck when summer comes around.

 

[NYC570]

The rear ac on my LX takes longer to cool than the front.

 

[MrX]

There is virtually nothing online about the issue I'm having, it's mostly with the 100s instead. As in, I don't think this happens much.

 

[zink]

I have had my '17 LX since new. I noticed the rear air was not blowing cold, about a year into ownership - front was fine. I took it in to the dealer they evacuated the refrigerant and recharged, adding some dye. Turns out it was 1/2 pound low. It's like an ice box now. I check with a black light periodically and no leaks. Worth checking.

 

[MrX]

Does anyone know how to pull climate control codes on these?

I've done it on my LS430 before.

Hope this isn't an expensive repair, but I can sell it to a dealer for at least as much as I paid and start over I guess.

 

[bloc]

Search for techstream in this section. And be aware that some of the cheaper cables won’t give live data that can help tremendously with troubleshooting. The VCX nano (could be wrong on this, but it is something like that and there is a thread devoted to it) should get you going.

 

[MrX]

Warm again today. Hmm? There is virtually NOTHING online about 200s with rear air problems. Just my luck. The previous owner never used the back seat, his wiener dogs were the only two living things that ever got back there.

Surely these trucks are engineered to be easy to service...this isn’t a Maybach. Surely I don’t need to go get ripped off at the dealer to look at this?

 

[1world1love]

Have you checked the FSM to troubleshoot? Have you checked all fuses? Have you hooked up tech stream? Or what other steps have you done at this point?

Does it change temp at all when you adjust? Can you disable 4-zone and set the temp from the front? Is it the same then? With AC turned off, does it change normally from hot to cold as you adjust the temp setting (both in front and in back?

I would first check all possible controls and see what changes. Remove all possible variables, so turn off 4-zone so that there is only one control point. Also turn AC off and the cold box. Then max the temp setting and see if it blows hot in front and back the same. Go down in 10 degree increments and make sure that it feels the same at all outlets.

But checking fuses and checking if there are any codes would be my first stop.

 

[MrX]

Have you checked the FSM to troubleshoot? Have you checked all fuses? Have you hooked up tech stream? Or what other steps have you done at this point?

Does it change temp at all when you adjust? Can you disable 4-zone and set the temp from the front? Is it the same then? With AC turned off, does it change normally from hot to cold as you adjust the temp setting (both in front and in back?

I would first check all possible controls and see what changes. Remove all possible variables, so turn off 4-zone so that there is only one control point. Also turn AC off and the cold box. Then max the temp setting and see if it blows hot in front and back the same. Go down in 10 degree increments and make sure that it feels the same at all outlets.

But checking fuses and checking if there are any codes would be my first stop.

Thanks. What is the "FSM"? I agree with removing all variables. We checked the air filter, and the controls.

I have disabled 4 zone and set it to low in the front, still warm rear air. I sat in the back and set it to low with 4 zone turned back on., still no dice. Pretty sure it's not a switch or control issue.

It's going to be cold here tomorrow night conveniently so I'll test the heat out back there.

I know how to pull climate codes on my LS430 but not on these.

Mr Cool is right down the street and has excellent reviews. These rigs have to have been designed to be easy to service, as proper trucks should, right?

I don't want JoeBlow messing with my truck if it's super complex to dig into. I avoid the dealerships out of warranty unless there's no choice.

 

[MrX]

Have you checked the FSM to troubleshoot? Have you checked all fuses? Have you hooked up tech stream? Or what other steps have you done at this point?

Does it change temp at all when you adjust? Can you disable 4-zone and set the temp from the front? Is it the same then? With AC turned off, does it change normally from hot to cold as you adjust the temp setting (both in front and in back?

I would first check all possible controls and see what changes. Remove all possible variables, so turn off 4-zone so that there is only one control point. Also turn AC off and the cold box. Then max the temp setting and see if it blows hot in front and back the same. Go down in 10 degree increments and make sure that it feels the same at all outlets.

But checking fuses and checking if there are any codes would be my first stop.

Thanks. What is the "FSM"? I agree with removing all variables. We checked the air filter, and the controls.

I have disabled 4 zone and set it to low in the front, still warm rear air. I sat in the back and set it to low with 4 zone turned back on., still no dice Pretty sure it's not a switch or control issue.

It's going to be cold here tomorrow night conveniently so I'll test the heat out back there.

I know how to pull climate codes on my LS430 but not on these.

Mr Cool is right down the street and has excellent reviews. These rigs have to have been designed to be easy to service, as proper trucks should, right?

I don't want JoeBlow messing with my truck if it's super complex to dig into.

 

[TheGrrrrr]

On my LC, (not LX) there is some AC equipment in the driver side rear quarter panel, so I don't think it all runs off one system. You will see that there is a tennis ball sized air intake in the cargo area on that side behind the grill. Make sure its not obstructed. Maybe there is some equipment back there that needs serviced. FSM is the Factory Service Manual. I'm sure you can find a link to download it somewhere on here.

 

[bloc]

On my LC, (not LX) there is some AC equipment in the driver side rear quarter panel, so I don't think it all runs off one system. You will see that there is a tennis ball sized air intake in the cargo area on that side behind the grill. Make sure its not obstructed. Maybe there is some equipment back there that needs serviced. FSM is the Factory Service Manual. I'm sure you can find a link to download it somewhere on here.

There are technically three evaporators and blowers, one in the front, one in the rear, one in the coolbox. But only one compressor & condensor, meaning the refrigerant is all in a single primary circuit with a few different branches. Also two heater cores.. one front and one rear. Each of those has blend doors that mix hot and cold air to get the desired set temp.

 

[Blackbirdaerial]

I’m having the same issue in my 2008 LC. Sometimes it feels barely cold and other times just warm. All the while the front is ice cold.. I was sitting in the back tonight and I could feel the right side was cooler than the left. I’m left dumbfounded. It’s only the vents on the roof that blow warm

 

[MrX]

There are technically three evaporators and blowers, one in the front, one in the rear, one in the coolbox. But only one compressor & condensor, meaning the refrigerant is all in a single primary circuit with a few different branches. Also two heater cores.. one front and one rear. Each of those has blend doors that mix hot and cold air to get the desired set temp.

So, I'm guessing it's an expansion valve or something if all the freon is one thing. I feel like it going to be something that costs either $50 or $3000. Lol this truck is so clean and was so well looked after it's ridiculous. Just my luck. Lol. I swear the day after the first day I noticed the warm air, it was cool the next day.