1999 f150 XLT 5.4 4X4

HI,
This truck cannot control temp from inside.

When I bought the truck, the seller showed me a wing nut inside engine compartment on a hose. He turned it clockwise to make the ac colder and told me to turn it the other way when I need more heat.

It didn't occur to me that this was the only way to control the temperature unto i needed the heat and there was none (until I opened the hood and twisted the singular l wing nut).

Obviously this isn't the intended operation.
Is this a major problem? Or something easily corrected? (See Pics)

 

LOL that's not factory, Ford's do not use a control valve on the heater hoses to the core like that. They were probably too cheap to fix the blend air control door that switches between heat/cold.

 

You see the truck and don’t bother pushing buttons and turning ***** before you hand over money?

Yikes.

That aside, it’s not a problem if it does the job for you and you don’t have to wear enough layers of clothing to not fit in the driver’s seat . The HVAC blend door is no doubt broken and that does take some work/expense to fix.

 

Hot coolant runs thru the heater core all the time.... The "blend door" mixes air from the heater core with cool air to get the temp you want... Your door is broken so you are ALWAYS mixing ambient air with the HOT air in the winter and air conditioner COLD air with the ambient in the summer.. so NEITHER is working good.. Shutting the VALVE ON THE HEATER HOSE shuts off the water to the heater core for the summer... Thats a good CHEAP fix ... as long as you have adequate heat in the winter .... cheaper than fixing the BLEND DOOR.

 

They make a universal cable-operated valve for that function.

Here's an example, plus a control cable. I might try it myself if my blend door goes bad.

https://www.oreillyauto.com/detail/c...e/mry0/74827?0

https://www.napaonline.com/en/p/BK_7...ng_dcoe_google

 

Until they open that valve and find the lack of coolant in the core has allowed corrosion to set in. Primary reason Ford stopped using heater control valves, back in the 70's or 80's IIRC, because when they do, they get a floorboard full of steaming coolant. Cheaper in the short run, more expensive in the long.

I can certainly understand someone not having the funds to do that job, there's nothing easy about it. It's a double edge sword at best.

 

Thanks, but I'm going to fix the blend door.
itxs really a cheap fix. Since I do the work myself, it's less than $20

thanks....

 

To be clear, it hasn't been confirmed that the blend door is bad. It could also be the blend door electrical control, or the blend door actuator/motor. It was just a good guess that the "wing nut" valve was installed because of a blend door problem.

Do the diagnosis on the blend door before tearing in to it. I'd guess that you found one of the "cut a hole here" blend door videos, since the removal of the dash method is a big job.

 

There is no electric blend door actuator on his 1990
His blend door is cable operated, and the mechanism sucked from jump street
We were constantly fixing them under warranty

 

First step is to disconnect the cable and manually move the blend door and see what happens
Hopefully the door is not binding, bent or broken
A real pain to R&R the HVAC case to replace it
40 dollar part, 1100 dollar labor

 

He said 1999.

 

I stand corrected

 

Funny, but I just noticed my blend door or the motor making a creaking noise today when I had the Panel/Floor selected and adjusted the heat. I hope the noise is normal.

 

Understood.

Thank you