Expy 2003 - No heat - Just replaced thermostat

[RoadRunner42]

Expy 2003 288k - no heat, good ac, strong power of the blower - just cold as hell, and I just replaced the thermostat. Could this be the heater control valve? I have no records of it being replaced, and I didn't replace it. It's OEM, as was the thermostat.

I am recovering from a thermostat issue - it all kind of blew up - no chocolate milk so that's good, but regular fluid looked like orange milkshake everywhere! I had the shop fix it - I thought it was the kiss of death head gasket and the poor thing was done for - but it was just the thermostat and some hoses. No mention of them replacing anything else.

I had heat last year. My AC is just fine. If I were to assume that it was not the heater core, or the blend door (replaced actuator in the rear a few months ago for ac in the rear and it's mediocre still) could it be the heater control valve in the passenger side front engine?

I tried to test the part, I felt no vacuum from it, nothing blowing from it, and the line sucks clear. I honestly don't know much about the part, and can't find much either. When I pulled that line to test for a clog, the line was so brittle it broke at the rubber fitting that attaches to the valve. I bought a new HCV and am ready to put it in - with the line repair rig- I had to make a rig of a few pieces (including the inside of a pen as a coupling to make the line work) but in my ignorance I didn't know that it is part of the closed system of the radiator fluid circle cycle, and if I replace it there is going to be a fluid mess that I can deal with but I risk air in the system. So cabin heat comes from that process through the TINY brittle vac line and pumps to the cabin? This is what I'm not understanding.

Could that part actually be the problem of no heat in the cabin? Or do I need to just put that rigged line back into the pump, return that part, and do the heater core hose slice, tee, and flush? Or just be happy with a blanket and a winter hat?!

 

[AWAR]

The inline vacuum valve shuts off the heater flow when the air conditioner is requested. I bought a replacement valve at Napa. You could use a hose coupler and eliminate the valve for this winter. Flush the core with the valve removed.

 

[RoadRunner42]

I did get the valve from Napa. I'm looking into flushing without the valve, but I didn't want to slice the hose that it seems that I have to slice to so it. The valve doesn't seem to be the issue, but there still could be an issue farther down the tiny vac line that I can't see - the one that cracked close to the valve. Still troubleshooting.

 

[whtbronco]

You should not need to cut any hoses to remove the valve for inspection or replacement. It's just a butterfly valve so you pull the hose off 1 side and move it back and forth to figure out if the valve works.

You can also unhook the vacuum hose, plug the hose, from the valve so it remains open, default valve position is open. Then with the HVAC turned off start the truck and wait 'til the thermostat opens. You should feel the coolant hose is hot on the inlet and outlet sides of the valve and the return line from the heater core should also be hot if coolant is flowing through the heater core.

If you remove the heater valve you will introduce some air into the system. These vehicles have no bleeder so you just gotta run it for a few cycles and the air will work it's way into the over flow tank. Check the over flow tank to ensure it remains full. Nothing to worry about here.

The vacuum hose actually closes the heater valve when cool air or A/C is selected . Otherwise there should not be any vacuum to the heater valve.

 

[Drae]

Any time I had a heat issue with my 03 was due to severely low coolant and the time the actuator behind the radio/glove box area failed. You can try slapping the underside of the dash area to see if the actuator frees up.

 

[RoadRunner42]

It's freezing cold today - actually had some snow flurries!

I did check the actuator door on the passenger side, and it does move. I heard it, but it did sound slow if that's a thing. I have replaced one of the ones in the back back earlier this year, but I guess there's quite a few of them!

I don't have any movement or vac from the heater control valve. I did remove and replace part of the vacuum line, and I plugged it. Nothing. I don't get a flow or pull from the line or the valve. I have the valve just haven't had a chance to put it in. I do see how to do it without cutting anything...hopefully I won't crack anything either!

I was looking at the heater core flush, and I believe I can see how to do that without cutting as well - I saw someone put a nice valve in there so that they could access it faster and that was cutting the line to put it in. Which I'm not totally opposed to right now. It's cold and if cutting something is it, I'm in. I think Wednesday I will be able to give it a go...working 14 hours a day until then!

 

[whtbronco]

There's multiple actuators up front all on the passenger side of the dash. Below is some info for the DATC/EATC system that might help.

BTW, did you check for hot coolant hoses on both sides of the heater valve? The heater valve should be open without vacuum, so coolant "should" flow through it. If you don't have vacuum at the vacuum hose you have an issue with the EATC module or the vacuum supply to it.


Temperature Blend Door Actuators
The DATC system utilizes two temperature blend door actuators to control two separate temperature blend doors that independently vary the LH and RH side temperature settings, as desired. The temperature blend door actuators:
- are located on the plenum chamber.
- move the temperature blend doors on command from the DATC module.
- contain a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the temperature blend door.
- receive a reference voltage to one end of the potentiometer. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the DATC module and is matched with an expected wiper voltage value. The DATC module then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage match the expected DATC module wiper voltage value.


Vacuum Control Motors
The three vacuum control motors have the following characteristics:
- They are actuated by the ATC solenoid and manifold based on input from the DATC module.
- They position the mode doors to direct system airflow to the vehicle interior as determined by the DATC module settings.
- The air inlet door vacuum control motor is a single-diaphragm actuator with a single vacuum source.
- The airflow mode door vacuum control motors are double-diaphragm actuators with two separate vacuum sources to allow the actuator to fully retract or partially retract.
- When vacuum is applied to both vacuum sources, the actuator will fully retract.
- When vacuum is applied only to the partial stage vacuum source, the actuator will partially retract.



The vacuum control motor looks to be rather time consuming to replace.
REMOVAL
1. Remove the instrument panel. Refer to: Body and Frame, Interior Moulding/Trim, Dashboard/Instrument Panel, Service and Repair, Removal and Installation.

 

[RoadRunner42]

I did check the temp at the hoses. I did not have vacuum at the engine heater control motor, but misunderstood which way was open and closed, so for the heat, it wasn't going to matter, but for ac, yes. Correct? The one in the diagram looks the same as the one in the engine compartment passenger side, but not inside the truck. I had to rebuild that line anyway.

I'm currently doing the blend door actuator, and having a heck of a time with it without taking the dash off. I need to drive daily so I can't take that off without a day to do it. I can't see where this vac motor is again without taking the dash off, so I'm going easiest to troubleshoot and get to first.

I WAS able to get heat by using the obd tool and my ipad to tell the door to open. I did hear it open before so I assumed it was good, but when I made it open (or close don't know which way was what) through the app, I had heat. So I'm going on that, and my way of getting to the easiest thing first. I have 3 actuator parts, and watch them all be the wrong stem! I"m still trying to get the sucker out right now. I've got 2.5 bolts out.

 

[whtbronco]

If you got the actuator to work with the ODBII then it sounds to me like it's working. The issue might be the HVAC module not sending the correct signal.

For clarity the coolant heater valve is open without vacuum, and closed when vacuum is applied. So when the vacuum hose is disconnected from the heater valve it should still flow coolant and there should be no vacuum pressure from the disconnected hose.

The dash is tough and time consuming to remove. I'd avoid it if possible.

Have you by chance run the EATC/DATC self test, I may be assuming you have EATC in your truck. If not here's the DTAC module self test from @Hamfisted

DATC test.

Key - ON / AC - OFF
Push the OFF and FLOOR buttons simultaneously / Release and push the AUTO button within 2 seconds of release.
Let head unit run through it's test ( 30 sec ) .
Note code displayed ( B-code ).
If no faults all digits will illuminate. Press DEFROST to exit test or reset system.

Ford HVAC DATC Self Test Procedure

 

[RoadRunner42]

It didn't work. I got that darn thing in, I did have one that fit, and it's still doing the same thing. No signs of heat. I didn't properly calibrate? I'll try that again tomorrow at lunch I guess.

I do have a digital display air system, but it is single temp only - each side does not get to choose what they want. There is also NO power button. There is Auto, and Off.

@whtbronco I do see the link for test from youtube. Mine might do that, and I'll try tomorrow. That's more like mine - no on or off. Very frustrated tonight.

 

[whtbronco]

I did check the temp at the hoses. I did not have vacuum at the engine heater control motor, but misunderstood which way was open and closed, so for the heat, it wasn't going to matter, but for ac, yes. Correct? The one in the diagram looks the same as the one in the engine compartment passenger side, but not inside the truck. I had to rebuild that line anyway.

I'm currently doing the blend door actuator, and having a heck of a time with it without taking the dash off. I need to drive daily so I can't take that off without a day to do it. I can't see where this vac motor is again without taking the dash off, so I'm going easiest to troubleshoot and get to first.

I WAS able to get heat by using the obd tool and my ipad to tell the door to open. I did hear it open before so I assumed it was good, but when I made it open (or close don't know which way was what) through the app, I had heat. So I'm going on that, and my way of getting to the easiest thing first. I have 3 actuator parts, and watch them all be the wrong stem! I"m still trying to get the sucker out right now. I've got 2.5 bolts out.

Based on the above it sounds like a module issue, the EATC. Since the OBDII scanner was able to send the command for heat and you got heat that tells me the individual components are all working. Such as the actuators and heater valve.

I believe yours is called the EATC, electronic automatic temperature control, vs the DATC which is dual automatic temperature control.

I think the test will work for the EATC.


Congrats on getting the actuator replaced, dang shame that didn't resolve it. How long did it end up taking to replace it?

 

[RoadRunner42]

Mine will not go into self test. It does nothing. @whtbronco the actuator took nearly 4 hours to do. I did pull the front half the dash almost all the way off so I could have 2 hands. The back screw I had to kind of wiggle up and push off because it wasn't going anywhere. I now have a new set of gearwrench flats that have then bendy head because that would have helped allot. I dropped one screw into never-land, so it's in with two screws. I found the cable at the top was being nearly sliced into by a support beam, so I padded that, and the orange cable or hose was preventing me from getting the actuator out and was hard to move out of the way in the right places to rotate that sucker out, and back in. I cold do it faster the next time, but it was a pain. I did the back ones last year, and they were easier!!

I'm back where I started though. I had heat last year. My thermostat blew. I took it in to be replaced. What would they have touched during this repair that might have made my heat go out?

 

[whtbronco]

4hrs sounds like pretty good time to me for that actuator. Yeah for sure the rear actuators are easier.

The only things under the hood that contribute to heat are the thermostat, heater valve and heater hoses. With your OBDII scanner you proved that all works.

If the EATC module won't go into self test mode I would suspect that is the problem. I doubt you can find a new replacement, so it would have to be used. My only other thought is if your OBDII scanner has the ability to test the EATC module or monitor the module when you press buttons to see if the button is actually sending a signal?

I'm not sure I'd run out and try to find a replacement EATC module just yet though. Maybe one of the more knowledgeable forum members will chime in with another idea here.

There are places like modulemaster.com that will reportedly rebuild/repair them. I have no experience though.

Here's a few replacement EATC modules on eBay:

2003-2005 Ford Expedition AC Heat Temperature Climate Control OEM 2L1H-18C612-AG | eBay

DONOR VEHICLE: 2003 Ford Expedition. No hardware is included, unless pictured. Northwest Specialty Dismantling Inc.

www.ebay.com

03 04 05 Ford Expedition Temperature Climate Control AC 2003-2005 2L1H-18C612-AG | eBay

ALL INTERNATIONAL SALES ARE FINAL.

www.ebay.com

That said I know my daughter, stationed at Fort Stewart in GA, said they have like a dozen u-pull-it salvage yards near Savannah. So a local salvage yard might be a good option and save the shipping time and charge. There were 7 salvage yards in my town 23yrs ago. Now there are none, :-(.

 

[RoadRunner42]

I'm not sure it's the issue either, but it's easier to replace than some other weird parts. So, I did have to go into the country yesterday to set up a computer for someone, and there was a nearby junkyard....and after 14 expeditions, I found one. In my excitement, I think I pulled one for dual heat though. But I did get a few vac lines to try because mine is built from a pen and some zip ties! And I also found a few other little parts I've needed. Took my kid, and he found it weird but fun - plus he pushed the wheelbarrow and carried my tools, so that was nice! There are a bunch near me but prices vary...If I did get the wrong part I'll sell it on ebay, and I'll try to find another in the next week. These get picked over really fast - like zero of 15 had a fuse panel, and I'm near needing a new one of those too. Will update when I have a chance.