A/C Problem - blowing hot air

Thanks Joe..I read over those pages and bookmarked them for future reference, great info. I'm still at a loss for how this randomly happened. Don't really have the know how to check these things. I do have a multi-meter in my arsenal though...
 
So, can you control where the air comes out (windshield, dash, floor)? If you can, then those things are at least partly working. The DCCV code is why you get nothing but heat.
 
Yes I can control where I have heat come out. The windshield doesn't seem to be working 100% though. I feel something, but not blowing too much. You think it's the DCCV? Isn't it strange that it was working earlier and then this all happened after installing radio?
 
The DCCV, the wiring to the DCCV, or the DATC. That 2nd link has the tests to determine which it is. (It usually is the DCCV.)
 
joegr said:
The DCCV, the wiring to the DCCV, or the DATC. That 2nd link has the tests to determine which it is. (It usually is the DCCV.)
Click to expand...
Hey Joe,
So, I have no idea how but, I made it almost through the entire summer in NC with no A/C (didn't fix my issue yet). Pretty sure my degas tank is starting to crack as some coolant is starting to leak. So I bought the usual and also added in the OEM DCCV. I'm having a LS fixing party this weekend! Parts will all be here tomorrow.
Hopefully my issues will be rectified with all new plastics and a new DCCV. Now, I know there is no blend door on these cars, but I have seen some (actuator?) that sits behind the glove box, I believe. I am having issues where the windshield defrost vents will not function properly. Could this actuator be the cause? Also, not sure if it is related, but I can a sort of clicking behind my dash, like something is trying to open/close, like a blend door (again, I know this isn't a thing) but it has me scratching my head big time. Is it the 'mode door actuator, yh-1852' that is throwing the B1676 and making the plastic rubbing sound?
Also, I have attached my FORScan DTCs, if that helps.
DSM - B1676
DDM - B1676
EATC - B2799
EATC - B2798
MC - U1262
IC - U1262
IC - U1041
GEM - B1676
REM - B1276
EPB - U1058 (parking break works, but every once in a while, I get the check parking break light on my dash)


Thanks for all you do, guys. This forum makes owning my beauty/beast so much easier!
 
NickyCapo said:
...I have seen some (actuator?) that sits behind the glove box, I believe. I am having issues where the windshield defrost vents will not function properly. Could this actuator be the cause? Also, not sure if it is related, but I can a sort of clicking behind my dash, like something is trying to open/close...
Click to expand...

There is no air temperature blend door, but there are four air direction doors, and four actuators to go along with them.
The one that you are seeing behind/under the glove box is the actuator for the fresh air/recycle door. The one for the defrost is on the driver's side of the air box. I don't know, maybe if you took the instrument cluster out, you might be able to see it. The book says the whole dash has to come out to change it.
 
joegr said:
There is no air temperature blend door, but there are four air direction doors, and four actuators to go along with them.
The one that you are seeing behind/under the glove box is the actuator for the fresh air/recycle door. The one for the defrost is on the driver's side of the air box. I don't know, maybe if you took the instrument cluster out, you might be able to see it. The book says the whole dash has to come out to change it.
Click to expand...

Well this is exciting. I have bookmarked deneau, the section about this defrost door actuator. I'm reading just the instrument panel would be sufficient; lets hope this is the case. Would it be safe to assume the 27 99 and 27 98 codes are the DCCV? The defrost door actuator isn't going to affect me getting the AC working properly, is it? It's just going to affect the defrost vents to not operate properly?..
 
Yes, those are for the DCCV.
The defrost actuator problem can mean no defrost air, or it can mean always defrost air.
Yes, on re-read, it looks like the dash only has to come out for the panel actuator, so you're pretty lucky there.
 
joegr said:
Yes, those are for the DCCV.
The defrost actuator problem can mean no defrost air, or it can mean always defrost air.
Yes, on re-read, it looks like the dash only has to come out for the panel actuator, so you're pretty lucky there.
Click to expand...

So did all the cooling components, including DCCV. No leaks as of yet, nor overheating. I am now not getting constant hot high, it is noticeably cooler at 60degrees, though it also isn’t ice cold. I’ve only bleed the system once, should I do it a couple more times? Will that help the air get cooler? I’m almost positive that the ac was recharged when I bought it in March. Not too knowledgeable with this stuff. Thanks for all the help thus far!
 
Bleeding is not going to help with the AC not cooling enough.
Does it cool much better driving down the road at 60, or is it about the same?

Same - Time to check refrigerant pressures (both high side and low side) and compare them to the chart.
Much better - Time to check the engine cooling fan. If it's okay, then it could be the scroll control valve. Refrigerant pressure checks at idle and at 2500 RPM could confirm or rule that out.
 
joegr said:
Bleeding is not going to help with the AC not cooling enough.
Does it cool much better driving down the road at 60, or is it about the same?

Same - Time to check refrigerant pressures (both high side and low side) and compare them to the chart.
Much better - Time to check the engine cooling fan. If it's okay, then it could be the scroll control valve. Refrigerant pressure checks at idle and at 2500 RPM could confirm or rule that out.
Click to expand...

I would say it’s about the same. I’ll double check though. Guess it’s time to do some research on refrigerant pressures...
Thanks again!
 
joegr said:
Maybe, but low on the list of possibilities.
Click to expand...

I spent the better part of last night researching hvac systems on vehicles, and more specifically on our LS’s. I now see why you recommended doing that test. I’m going to see if my buddy has a manifold gauge set I can use, or just go buy one.
Like I said, I’m still learning but, it appears the ac compressor clutch is not engaging.
Would it be beneficial, before I get my manifold gauge, to try swapping the relay with a identical one or shorting our the two pins to see if I can engage the the compressor?
 
I wouldn't run the compressor without knowing that there is reasonable refrigerant pressure in the system. A bad relay is possible, but since the LS is not a cycling system, the relays tend to last a long time. I'd look at pressure first. If you don't have at least 50 PSI of static (non-running) pressure, then it won't turn the clutch on.

If you find that you have reasonable pressure, then the next thing to do would be to unplug the evaporator temperature sensor. That's the other main thing that can keep the compressor off.
 
joegr said:
I wouldn't run the compressor without knowing that there is reasonable refrigerant pressure in the system. A bad relay is possible, but since the LS is not a cycling system, the relays tend to last a long time. I'd look at pressure first. If you don't have at least 50 PSI of static (non-running) pressure, then it won't turn the clutch on.

If you find that you have reasonable pressure, then the next thing to do would be to unplug the evaporator temperature sensor. That's the other main thing that can keep the compressor off.
Click to expand...

Sounds like a plan to me. I will report back after the pressure test.
Again, thanks a lot!
 
most recent discovery replaced with junk yard dccv to note both jammed on 1 side managed to clear out one re installed worked for 1 night after flushing next day mixed output to vents
there is no codes here I express possibly a fresh dccv pristine ......possible other factors as problems with system the out put sensors are behind the dash untried and did try 2 separate climate control brains both with similar results come up good diags but no change to mixed outputs there was a hot relay for one side of the dcc which leaves me to suspect possible other problems ….. ive given up on multi sensors and just bypassed the heater core and disconnected the auxillary fan ive caped the heater core inlet line at the tree and at the main radiator hose port to the dccv also made a circuit out of the dccv out and auxillary coolant motor tube nice and neat leaving the coolant as to later convections ….its nice and cold now I might remove the relays to the dccv as well the auxillary coolant motor …… *** to note important to be patient when refilling your coolant use the purge valve a few times or you will get hot sucking boiling coolant in your degass as well when connected properly in your heater core this I cant express enough as when buying the car the dealer was forced to replace the degass bottle poping open during test run ..there is way to much pressure so a short idle run or two is advised until you relieve the system and get the proper level of coolant :(:mad::confused::cool:
 
You can't add relays in-line with the DCCV. The DCCV is pwm controlled, and the relays won't work with that.
 
Not to start a new thread, I decided to latch onto this one.
My system just started blowing hot air on the driver's side and cooler air on the passenger's side, and one of the codes is 2798 - driver Coolant Control Valve circuit short to ground. I also have codes 1265, 1264 & 1262, but the system works fine deflecting air flow where requested (and as joegr mentioned above, the 1265 is an invalid code for the 2005 model year).
My question is: Could this fault related to the 2798 code also be the cause for the screen on the THX Nav system to have horizontal flickering lines?
 
LSV8FAN said:
...My question is: Could this fault related to the 2798 code also be the cause for the screen on the THX Nav system to have horizontal flickering lines?
Click to expand...

As it turns out, yes it can. I have seen this before. You can unplug the inline connector for the DCCV (it's easier to get to than the one on the DCCV itself) or the connector at the DCCV, and verify that the flicker goes away (passenger side will get hot air now too).

I unplugged my DCCV when it started to fail while waiting for a new DCCV to get here. I figure that the added stress to the DATC and the added electrical noise to the rest of the car can't be good for the continued life of the rest of the parts.
 
Thanks joegr. I did pull fuse #1 (10A) from the under-hood power distribution box and the flickering stopped. That fuse also controls the A/C clutch and the auxiliary coolant pump. From the inline connector that's easier to get there are 2 branches, one to the DCCV and the other probably to the auxiliary coolant pump (assumption based on what the fuse controls). My concern is disconnecting the auxiliary coolant pump and the effect it may have on engine cooling. I'll try to modify a blade screwdriver to access the connector at the DCCV, unlock it and disconnect it.
 
You won't have any engine cooling problems with the aux pump disconnected.
 
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