My full-on heating problem (Advice needed)

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snewo

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2004 Lincoln LS8 One day while parked with the car running, the AC just decided to start blowing full heat out of both driver and passenger sides. Right off the bat I suspected the DCCV. Sooo....I ran the diagnostic. I get a 2798 and 1265. Throwing out the 1265, I went to climate pinpoint tests.

Pinpoint tests say that I should run Pinpoint check H for a 2798.

H1 -> Yes -> H4 -> Yes -> Test is complete.

Well that wasn't helpful. Not knowing what to do next, I decided to look at Pinpoint J since it is for full on heat in all modes.....I went down this rabbit hole:

J1 -> No -> J2 -> I assumed I was supposed to measure for voltage on the cable side and not the DCCV side (since that didn't make sense to me) -> no voltage -> Install a new DATC


I'd just like to run the above by everyone here to make sure I'm approaching this properly. Should I change out the DATC? I really thought I was going to find the DCCV as the cause of the problem so I'm doubting my troubleshooting above.

I read that the new DATC needs to be configured for the vehicle. Does that make this an item where I will need a dealer? It would be nice if I could just swap a Gen 2 with a Gen 2 by yard.


Other info you may ask
- AC works fine when car starts initially before it has a chance to heat up.
- Even with the climate control off, the front interior of the car gets warm. I mount my phone on a vent and it's warm when I take it off.
- Both hoses leading into the passenger compartment are hot.
- Car blow heat even with DCCV unplugged

Any help you can provide would be appreciated.

Thanks in advance!

-Snewo
 
I think that the way you measured for voltage is probably suspect. Did you check the DCCV fuse? (A bad DCCV can blow this fuse, then cause a no voltage measurement.) I'd still bet on the DCCV.

(No, the DATC does not need to be configured.)
 
joegr said:
I think that the way you measured for voltage is probably suspect. Did you check the DCCV fuse? (A bad DCCV can blow this fuse, then cause a no voltage measurement.) I'd still bet on the DCCV.

(No, the DATC does not need to be configured.)
Click to expand...


You're spot-on. I just checked the fuse and it's blown. I'll pop over to grab a new one and test the voltage on the plug with a good fuse.
 
snewo said:
You're spot-on. I just checked the fuse and it's blown. I'll pop over to grab a new one and test the voltage on the plug with a good fuse.
Click to expand...

After replacing the fuse I DID have voltage on both connectors during the J2 test. That points to a bad DCCV according to the pinpoint tests. For fun I replaced the connector and fired up the car.....blew the fuse right away.

The fuse that I missed is exactly why I posted here to the experts. Thanks joegr for catching it.

Now to talk about changing out the dccv. I was planning on buying some hose clamp pliers and swapping out the dccv without draining the coolant. Has anyone tried that? Am I stupid for thinking about doing it that way? Will I need small hands? Whataya think experts?
 
Someone on here has done that before. Hose clamp pliers don't clamp down on hoses, they allow you to remove the spring type hose clamps. Two very different tools.
You don't have to drain that much coolant to do this, and it is much easier to do if you remove the upper radiator hose anyway. You should change out all your coolant every five years anyway.
Be sure to get the Motorcraft DCCV. I tried the aftermarket one once (it's all I could get on short notice). It starting failing in a month or so.
 
joegr said:
Someone on here has done that before. Hose clamp pliers don't clamp down on hoses, they allow you to remove the spring type hose clamps. Two very different tools.
You don't have to drain that much coolant to do this, and it is much easier to do if you remove the upper radiator hose anyway. You should change out all your coolant every five years anyway.
Be sure to get the Motorcraft DCCV. I tried the aftermarket one once (it's all I could get on short notice). It starting failing in a month or so.
Click to expand...

I'm not sure what most people call them, so I just used the name from this website: Hose Clamp Pliers Set | Tool Aid
 
Just last Sunday I did my dccv and was going to do it by pinching off the hoses just as you are planing. Not long after I got started I realized, just as joegr stated, that removal of the top radiator hose would make life much easier. So I drained the radiator and removed the top hose, not that big of a deal. In my 04 v8 I drained around a gallon of coolant, maybe a bit more. All you need are a new dccv, and 1 gallon of coolant, use motorcraft for both, and a gallon of distilled water. Remember 50/50 mix of coolant and water and bleed the system.
 
Before replacing the DCCV, I would disconnect the electric plug from the DCCV, replace the fuse and see if it blows with the car running. While you likely have a bad DCCV you could have a short in the wiring going to the DVVC that is blowing the fuse.
 
also do the Coolant Auxiliary Pump - 5W4Z18D473A



pragmatic said:
... likely have a bad DCCV you could have a short in the wiring going to the DVVC that is blowing the fuse.
Click to expand...

Likely, however more so the fuse continues to blow as the internal Climate Control chamber solenoids are stuck. Coolant is a corrosive material, eats and gums stuff up. Entire cooling system suspected to be of same status.

pict0167_opt-jpg.57151.jpg


DATC currently has it instructed to move, which it can't.
Removing the electrical would stop the fuse blowing.
Climate control is ON, start car, fuse blows.


more: DCCV Disassembled Views
 
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pragmatic said:
Before replacing the DCCV, I would disconnect the electric plug from the DCCV, replace the fuse and see if it blows with the car running. While you likely have a bad DCCV you could have a short in the wiring going to the DVVC that is blowing the fuse.
Click to expand...

I did check and the fuse did not blow with the car running. Not until I stopped, reconnected the DCCV, then restarted. Thanks for the info though.
 
DATC currently has it instructed to move, which it can't.
Removing the electrical would stop the fuse blowing.
Climate control is ON, start car, fuse blows.


Try shutting the Climate control OFF before shutting the car down,
fuse would only then blow again once Climate control is turned back on and temp on either side is altered.

:: Potentially ::

.
 
RigsLS said:
...Try shutting the Climate control OFF before shutting the car down,
fuse would only then blow again once Climate control is turned back on and temp on either side is altered.

:: Potentially ::

.
Click to expand...

The DCCV circuit is powered with the car awake (climate control on or off).

snewo said:
I'm not sure what most people call them, so I just used the name from this website: Hose Clamp Pliers Set | Tool Aid
Click to expand...

Real hose clamp pliers
www.amazon.com/Astro-9409A-Hose-Clamp-Pliers/dp/B003D3N7YW/ref=sr_1_1?ie=UTF8&qid=1492434875&sr=8-1-spons&keywords=hose+clamp+pliers&psc=1

(Pliers that work on hose clamps, not pliers that clamp off hoses.)
 
joegr said:
The DCCV circuit is powered with the car awake (climate control on or off).
Click to expand...

Would you suggest it's attempting to move the solenoids while OFF? Even though its 'supplied' while awake, ... during OFF position, does the DATC demand it to alter the solenoid positions for desired temp?

While ON I could see. At least I believe so.


If the OP, turned the Climate control OFF while the ignition is cycled, then replace the fuse ... soon as the DATC is turned back on, it would blow the fuse again, I would think.

If the car is off, keys out and still in awake mode, Would it blow the fuse soon as you put a new one in? I mean although there is power going to it, it's attempting to move the solenoids? To full open, full closed or to last know desired selected temp request?


Either or the DCCV is faulty.
as pragmatic suggests a short is also possible.
.
 
+12V to the DCCV solenoids is not switched, other than with most of the rest of the power on the LS that stays on till the car sleeps. The DATC just switches the grounds on and off to the DCCV solenoids. It may be possible for them to short to ground via the metal bracket even without the switched grounds from the DATC, but I think that the bracket normally only touches plastic.

I would have expected that the DATC would not try to power the solenoids when the key is off, but I found out this was not the case (the hard way). The DCCV on my 06 developed a leak and a partial short (enough to detect and cause problems, but not enough to blow the fuse). With the key off, I could hear the DCCV still clicking away till I gave in and unplugged it for fear of it running the battery down. (With it running, I could also hear the electrical noise of the solenoid in the radio.)
 
All air flow settings on DATC
The dual coolant control valve is automatically controlled by the DATC module based on the temperature settings

When OFF is selected:
The dual coolant control valve is in the CLOSED position, preventing the flow of hot coolant to the heater core.


Positive side may very well be supplied through the fuse to the solenoids but if the DATC isn't completing the circuit because it's OFF, I would have thought it wouldn't do anything to even begin to blow a fuse.


I'm not disputing, I'll simply take your word for it.
 
You do understand that "closed" is when the solenoids are energized (powered)? What you copied, says that the DCCV is powered when the DATC is off. This makes sense. You wouldn't want the heater core radiating heat in the dash when the system is off, would you?

Don't believe it? Unplug the DCCV connector and notice that you get full heat (valves open).
 
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Didn't state anywhere that I didn't believe ya Joe. I was also already aware of that, simply failed to include it in my thinking. Knowing that the DATC controls the DCCV I failed at assuming it had to be ON before a fuse could pop.
 
I just thought I'd close out my comments on this thread. I did finally get around to replacing my DCCV today. I opted for the "pinching the hoses" method instead of draining the coolant. It was a tight space to operate in, but some fancy hand work and sore knuckles later she's back up and running as expected. If anyone is considering this method then I'm proof it's possible. What I can't tell you is if it would be easier through the draining method. Overall it took about 3 hours and that included a trip to the store to get long needle nose pliers that I needed for the hose clamps.

The AC is glorious again, just in time.
 
Rebleed the cooling system, despite "pinching the hoses", your new DCCV has introduced air into the system.
 
Thx for the reply. I did bleed the system...drive around and bleed it again. All seems well, it didn't really take up much coolant from my bottle. Overall it was a 4 Bounty towel cleanup of liquid. :)
 
Don't be so quick to close this thread out I want to come back and read "I told you so" threads when you come back and say it overheated two months later.

Cause you didn't do the proper steps.

Did you know that it is required to use the coolant bleed machine to get the air out. But you can do it manually but you have to follow it to the T.

I've. Been on this site for over six years 2002 ls v8 still up and running, and every time I cut a corner, I'm right back in a few months down the line thinking
Joegr, BigRig,ls8, and the other guys told me to do it this way and look I'm right back in.

Do it right the first time it'll save you in the long run

Trust me I know coolant gets costly after going in multiple times to bleed the systems cause you was being hard headed.
 
He might very well have gotten a bit of air out when he rebled it the first time and a tiny bit more therafter. He just didn't specify prior that he had already done so.

Pinching the hoses correctly then replacing the DCCV would in fact only introduce a much smaller portion of air into the system compared to completely draining it all out because the entire system was being refreshed.

Lets give him the benifits of our doubts. May very well have gotten that little air introduced all out of it. On the other hand, trapped air pocket may linger for a bit causing tempermental overheats.

I'm sure he'll keep an eye on it. Not like he doesn't have a vested interest in monitoring the degas level continuesly for the upcoming days.

PS - do let me know soon as you get no heat at idle but plenty at higher RPMs ... I suggested replacing the Auxiliary Coolant Flow pump for a reason. It all ages and breaks around the same time. Placing 10$ bet.
 
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