The best idea here is to add a vacuum operated heater control valve inline with the 3/4" heater hose feeding the heater core. This has been a standard on many cars & trucks for decades and is a non-issue for the heater core corrosion & engine cooling.

motorcraft part number YG389 heater control valve for 2003-08 Fseries superduty f250-550 sells for $14.

Not sure if it has 3/4" hose connections.

The trick is connecting the vacuum from the recirculation valve vacuum to the heater control valve with a tee and where to run the vacuum line.

Pinhead227 posted some pictures of recirculation valve, how did he run the vacuum hose from the recurculator valve vacuum through the firewall to the added on heater control valve???

thanks,

Jerry

 

I too thought this was the best bet... Until I did some research this weekend. Turns out that the 04+ F150's blend door is no longer vacuum controlled. It now has an electronic door actuator. So I don't think we can control the heater control valve off of vacuum now.

However, this may open up another opportunity... An earlier posted said that electronic heater control valves are also available. So we'd need to first locate an appropiate control valve, and then figure out what wire to tap into so that the valve only closes when the a/c is on MAX.

 

Sounds like your water control valve is inoperative.

 

???

Who are you talking to?

 

I ran the line through the passenger kick panel wall (behind the passenger-side fender) right next to the ECU. The vacuum line then came into the engine compartment behind the battery.

The blend door has an electronic door actuator (IIRC, the same as the Rangers), but the recirculate (MAX A/C) door should still be vacuum controlled.

 

I think I used the wrong term... What I'm referring to is the door that lets fresh air into the truck. I took off the glove box, and when I went from recirc to fresh air, I could clearly see a door opening and closing. It appeared to be controlled by a small motor on the left side of the door, with a small wiring harness attached to it. Nowhere did I see any vacuum lines going to/from it.

 

Interesting. Now my question, is WHY????

Vacuum has been used for the recirculate door since the beginning of time and very seldom has any trouble. I wonder why they decided to go to a (more than likely more expensive) electronic peace instead.

 

I looked at the system diagrams... It appears everything is electric motors; no vacuum at all for this system. They all have wiring diagrams.

-- Kevin

 

I wonder if you could just hook up an electronic heater control valve to the wire that illuminates the RECIRC indicator on the a/c control panel.

 

Pinhead227,

What year truck are the pictures of the vacuum recirculation valve you posted in post #101?

Looks like you drive a 1999 f150?

I saw a 12 volt, 3/4" x 3/4" 2 port electric coolant valve made by Thermotion part 740976WV that might be a candidate for a electrical heater control valve. I'm going to keep looking for others. Here's some links.

http://www.thermotion.com/Thermotion...cts/2port.html

http://www.thermotion.com/Thermotion...ater_Valve.PDF


Not sure what year F150 have electric recirculation door actuators and which have vacuum recirculation door actuators?

I’ll take a look at my 2008 F150 this evening and try to figure out if its electric or vacuum.

 

Could somebody please explain the concern about heater core corrosion?

How does the coolant's state (static or circulating) effect its ability to corrode my heater core?



Does the chemistry of the coolant break down, over time?

How much time are we talking about?

My coolant sits uncirculating for at 22 - 23 out of every 24 hours and sometimes for days or weeks on end... ... ... that a problem?

 

YAY! i have no ac

 

08_silver_xl,

I found an alternative to the Thermotion electric actuated heater control valve. Vintage Air makes a servo controlled heater control valve that could be actuated with either the recirculate or A/C circuit by using the appropriate relays. Don't know the cost of it, though.

 

Installed the "Lowes" 3/4 ball valve last night. Haven't had a chance to try it out yet, but should have some data in a few hours. If I don't get any results from this ball valve I'm done with this project! Just to make sure I'm not missing the boat I bought a canister of freon from checkers with a gauge on it. My system read like it had a good charge.

 

Been running mine a few days now - something has happened that I never experienced before with this truck - having to turn the A/C down because it was getting too cold. I've got a regular cab but there is definitely a difference...