Can someone please explain what on earth is up with my HVAC

Silver02Sport

Silver02Sport

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So I'm putting the LS back on the road & just had a rather confusing series of events. To start I had a new compressor, evap temp, & cabin air sensor installed & the AC worked but the stupid DCCV was acting up blowing hot on the passenger side & cold on the driver, Ok I order a new DCCV. Well a few days later she start to overheat so I put the heat up to 90 and it just blows ice cold air on BOTH sides. Well I pull over & find the t-stat housing crack so I have it towed to the shop & replaced afterwards she no longer overheats but the AC blows only HOT annoying since I live in south florida but the DCCV was in the mail. Well today I get the DCCV & have it installed and the AC blows cold on both sides now but NO HEAT. WTF????

so in short
New compressor & it blows hot & cold at once
Overheats & blows only cold
fix overheating & it blows only hot
replace DCCV and it blows only cold

Anyone got any ideas because I sure can't figure this one out.
 
Have you tried taking a tool to read the AC codes? Usually you'd need a dealer tool but if you've got a laptop you can run FORSCAN and it could help tell you what errors are going on with your AC system. USB to OBD is about $20 on Amazon FORSCAN is free.

It's really in your best interest to try and use a tool like that to figure out the specific problem over replacing things one by one costing you an arm and a leg. Good luck!!
 
Silver02Sport said:
... DCCV & have it installed and the AC blows cold on both sides now but NO HEAT. WTF????
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And what is fuse #1 underhood doing?
It'll read A/C CLUTCH

DATC module responding to different modes correctly?

Connector to new DCCV snapped in firmly?

OEM DCCV ?



~ No heat at idle BUT plenty at higher RPM's = Aux Coolant flow pump

:: Both solenoids within the new DCCV appear to be in the closed position if no heat is getting to the interior heater core. At such point both inbound hoses and return at the fire wall going to the interior should be cold to the touch. Once the Solenoids can be controlled correctly, 90F setting on the DATC or disconnect the harness connector from the DCCV would allow hot coolant to pass through to the heater core. Hoses going in at the firewall should then become hot to the touch.

If all else fails, then air in cooling system.


more: GEN I - Understanding Climate Control System - No Heat Information


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Silver02Sport said:
...
New compressor & it blows hot & cold at once
Overheats & blows only cold
fix overheating & it blows only hot
replace DCCV and it blows only cold

Anyone got any ideas because I sure can't figure this one out.
Click to expand...


Well ... it looks like your LS does not like you! :(

.
 
You have to replace the rest of the degraded plastic cooling system parts and then bleed it correctly. I'm 99% sure that this is all there is to your no heat problem.
 
RigsLS said:
Well ... it looks like your LS does not like you! :(

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Ya she's pretty mad at me for parking her for 3 years it's my fault but I'm sure she'll get over it once I've thrown enough money at her... eventually.
Till then no codes when I do the AC self test and my mechanic says his scanner isn't showing any issues I'll look into getting FORSCAN. The fuse is fine & the heat ain't working at any speed so I don't think its the aux pump. It can't be the heater core as it was blowing hot the other day. It could be a bad DCCV form ford (lord knows even the good one's seem temperamental) but I'm not pulling it again right now. Luckily I live in South Florida so the only thing I need the heat for is the defogger but still it would be nice is she'd stop putting up such a fuss.

I'm thinking joegr's right I just need to replace more of the plastic & bleed again as it took like five attempts to bleed just to get the thermostat to open. Well at least I know where to start now thanks.
 
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Yes, well this is the thing, as we always suggest, the plastic cooling system gets weak over the years, begins to rot from the insides and eventually springs a leak where the system then gets air introduced and starts giving us headaches with overheats, can't bleed and no heats.

Rebuilding it all at once with all brand new OEM parts is the only way to win.
 
RigsLS said:
Rebuilding it all at once with all brand new OEM parts is the only way to win.
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Ok other then the Alu t-stat housing which I've already installed are there any other plastic parts that can be upgraded to metal or am I stuck replacing plastic with more plastic?
 
Nope. Only the T-stat housing and cap is available in all aluminum from Jaguar for the 1st GEN only. Must use the Ford Lincoln LS Thermostat with that. All other plastics cooling components are OEM and only available in plastic. DCCV's and Auxiliary Coolant Flow pump's, including Degas bottles should also be replaced as a whole if older then 10yrs. If not, it'll simply be the next failure points.
 
Seems like some air left in your cooling system?

Suppose you don't have leak in the A/C system, and since it's now blowing cold air from all sides, the compressor and evaporator core is working normally. Now the symptom is no hot air(seriously, really cannot understand why you want it since you live in south Florida), it might be the case that the hot antifreeze fluid cannot flow though heater core, which heats up the air flow. And since you just replaced the DCCV with a good one, I think the culprit behind is the trapped air in heater core, which blocks the heat exchange.
 
And today it's back to blowing hot on the drivers side & cold on the passenger I'm starting to think the new DCCV is bad.

Tony_1992 said:
seriously, really cannot understand why you want it since you live in south Florida
Click to expand...

Well for starters I when I bypassed the heater core on my Jag and had to pull over several times because the windshield was fogging up in the rain & it's so hot & humid out the cold defogger just made matters worse.

Also while we have a yearly average temp around 85 we usually get a few cold weeks in the winter where the temp drops to the 60's in the day & the 40's-50's at night. I know that might not sound cold to you northerners but to this Florida boy that's cold. Hell there were even a few mornings when the heated windshield came on automatically & if I remember correctly that only happens when it's near freezing.
 
Any chance that you accidentally swapped the driver's and passenger's hoses?
 
Ok now things are getting really weird. It's been raining everyday for the last week & the issues started around the same time. I didn't think anything of it then but while it was raining this morning I got just heat come lunchtime it had cleared up & we had sunshine for the first time in a week & guess what the HVAC worked PERFECTLY. I'm thinking maybe some water is getting into some part of the harness & shorting something out. It's predicted to rain again tomorrow so I guess that will be the test.
 
Silver02Sport said:
I'm thinking maybe some water is getting into some part of the harness & shorting something out.
Click to expand...

This could be a possibility. Per another thread here somewhere recently... if you have a moonroof,,, the drains can plug or become disconnected... allowing water to potentially migrate into certain wiring harnesses.
 
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