After suffering musty A/C discharge to the point of having black mildew growing in the cab of my 2001 S’Crew Lariat, I decided it was time to clean the evaporator. I purchased a DWD2 kit (www.dwd2.com) – per a recommendation on this board – and used it to douche the evaporator this past Sunday.

Everything went fine with the installation and use of the kit. The kit worked as advertised and I was happy with the results – until Monday morning. While driving to work on Monday, I smelled something burning. I later noticed that my temperature blend controller was no longer working. Fortunately, since I live in Houston, it broke on a somewhat cool setting.

On Tuesday, I got to thinking that perhaps gunk from the evaporator coil crapped up the blend door mechanism, so while playing with the temperature controller, I pounded on the evaporator housing with my hand. The system went to full HOT.

Later on Tuesday, I drove the truck again and the system had returned to the somewhat cool setting it died on earlier.

I tend to think the problem lies in the blend door actuator, but after seeing photos of the blend door actuator (from a Mark VIII); I have a hard time believing that the actuator motor was affected by the foam cleaner. Also, why did it take a day to die?

I appreciate any advice from this board before I invest a lot of time and effort tearing my dash apart trying to locate the damage.

By the way, I have read the posts on the Explorer blend door failures and do not think that applies in this instance.

Thanks in advance,
Jeff

 

The LD F series blend door actuator is mounted on the bottom of the plenum, so if there was a large amount of goop in the case it could certainly have run down the blend door shaft and contaminated the circuit board in the controller.

 

Thanks for the response, Homerwinzlow,

I just removed the blend door actuator. After getting it off, I can see how liquid could run down the shaft and into the housing. Strangely, the housing is dry on the inside, but the actuator does appear to be dead. I will stop by the local dealership tomorrow and pick up a new one.

My next question is, when installing the new actuator, how do I match the position of the actuator with the position of the door? I can see how getting this wrong could damage the new actuator.

After following the Chilton’s manual, I still could not remove the floor ductwork, so I am working in tight spaces.

-Jeff

 

The actuator is squared on 3 sides and rounded on the fourth side. It will only fit one way. I recommend connecting it to the power lead, and turn the key on and set the temp control to midway. This will center it. Remove the power connector. Then place it into the opening of the blend door shaft working right to left untill you feel it seating into the shaft of the door. Then once fully inserted into place, align to the mounting bosses for the actuator and install the screws. Its easier without the duct there but if you cant remove it dont force it or you may break something.

 

Also note that the controller has fused power of its own, so ensure the fuses are all good.

 

Thanks. The fuse was the first thing I checked. Now that the actuator is out of the way, I will try removing the ductwork again. It's a puzzle trying to get the ductwork out. I prefer to have a clear shot at the actuator door when installing the new actuator.

Is there a way to safely test the actuator when not installed? Last night, when I had the actuator in my hand, I turned the system on and adjusted the temperature - with no reaction from the actuator.

I checked voltages, grounds, and continuity at the actuator plug before removing anything to rule out the controller or circuit.

-Jeff

 

If you have all the voltages and grounds then the actuator is highly probable. I have replaced hundreds of them over the entire lines of Ford vehicles. One good thing about them is that they are relatively inexpensive. Some are under 25.00

 

Homer,

Mission accomplished! Thanks for all your invaluable input.

-Jeff

P.S. It appears that the DWD2 evaporator cleaning kit was the cause of the actuator damage. On the 2001 F-150, the actuator driveshaft inserts into the bottom of the HVAC plenum to drive the blend door. This shaft was the leak path of the cleaner into the actuator.

 

Good to see you met with success... It may have just been coincidence that the controller went bad after you cleaned the evap, but its good food for thought for people to consider when cleaning thier evaporator that there may be electronic devices that can get contaminated if you use a large volume of liquid in the case that cant drainout fast and fills the case.

 

The DWD2 folks will tell you that there is only 9 oz. of cleaner in the kit. You should have seen what I had draining out of my evaporator when using it, though. I know my evaporator drain was not plugged prior to the cleaning, so that had nothing to do with it. Perhaps the cleaner, plus normal condensation being generated at the same time was too much for the drain to handle.

For future reference, what do the garages use to clean the evaporator? My Haynes book mentions a strong aerosol disinfectant sprayed through the opening where the fan speed resistor mounts, but all I could find at the local auto parts stores was some lame disinfectant in a spray pump.

-Jeff

 

FrigiFresh is a common one. Ford has its own treatment that you apply with a pressurized tank that sprays the evaporetor down in a mist. You runt the heater for 15 minutes, apply the treatment, let stand for 15 mins, then run the heat for 15 more minutes. (real fun in the hot summer) I dont think it lasts any longer than the others and is very expensive.

 

I went to the website for the evaporator cleaner. The cost was outragous. Bleach works fine,

 

Tobydanr,

I was thinking a bleach solution would be effective. How do you douche the evaporator coils without removing it?

-Jeff

 

I have a blend door actuator that opens and shuts blend door when the AC is on would this be a bad actuator