New to me 2003 F350. The truck has a vacum controlled heater valve in the heater hose. I looked at another 2003 and it doesn't have the valve, but it does have a vacum hose that connects to the evaporator housing. It's the same gray color hose that I have going to the heater control valve. Should my truck have the heater control valve?
Also there are a group of loose wires near the MC, my truck and the other truck both have them. What are they for?

 

The wires are pass through wires. There are 4 identical ends inside the truck behind the panel under steering culmn. You can wire stuff to them then pick it up under the hood so you don't have to put holes in the firewall.

 

The valve looks like the “Max AC” or “Ranger Valve” mod. It cuts the hot coolant from going into your heater core when you have the **** set to MAX AC. Look up either of those terms and you should get some hits to explain it.

On second thought, I’ve got a link saved for when I finally get around to doing it myself. I have the parts already. I’ll share it below.

https://www.ford-trucks.com/forums/1...ne-this-5.html

 

Thats exactly what it is.



This is mine installed.

 

Best bang for the buck mod evah!

FWIW I think your truck was in very good hands with the PO.

 

So some trucks had the valve in the heater hose from the factory?, which I'm guessing mine did. Interesting how the other had the vacum hose at the evap case. Mine has a nub on the case and I'm wondering if that's what the other trucks hose is attached to. For some reason my heater hose isn't routed correctly, it's like they used a new hose and didn't cut it and just attached it to the valve.
Interesting about the wires, I'll have to look under the dash for them.

 

No, the Super Duties did not come from factory with those valves, they are added by owners to maximize cold air ouput from the AC.

 

Correct.

Incorrect.

In 2002, Ford began installing the vacuum valve in one of the heater hose lines for all Super Duty pickup trucks and chassis cabs, regardless of trim level.

As an example, I ordered a 2003 F-550 XL bare bones chassis cab (with the 7.3L), and when I took delivery of the brand new truck, fresh off the transport truck at the dealership I ordered it from (in other words, no previous owner), I opened the hood to inspect it and there was the valve, EXACTLY the same as what @Eman85 showed in the photo of the original post, only without any dirt, because the truck hadn't even been driven yet.

My 2000 F-550 did not have the valve, but 2000 Excursions did.

1999-2001-ish Super Duty trucks did not have the valve, but later Super Duty trucks all came with the valve.

The factory implementation of the heater valve is different than the aftermarket implementation that most owners have done themselves.

 

I'm probably wrong on my above response but my 2002 did not have the valve. I am the second owner and the original owner is a friend who did not remove a valve, for what that is worth.

 

I've worked on dozens of 02-03 7.3s that have a valve stock. Not all - but some. Y2KW57 is correct.

The 6/02-built F350 that became the drivetrain/frame donor for the 1973 did not have one and neither does my brother's later 02 build F250 in regard to personal vehicles. The 2002 I used to drive as a parts chaser for my last employer didn't have one either.

 

To split a few more hairs, running production change intro dates can sometimes differ between Cuautitlan versus Kentucky.

I had to say "in 2002" (calendar year) because I do not know the specific date of introduction of the valve in Super Duty trucks between KTP and CSAP.

I just knew it was in calendar year 2002, and therefore it COULD apply to some (but not all) 2002 Model years, so 2002 model year could not be excluded.

But the 2003 model year, of which most of the 7.3L units were also built in calendar year 2002, definitely have the valve shown in the OP's truck, just like the '03 I ordered a couple of years earlier than needed, for the sole purpose of completely avoiding the 6.0L (which was already crippled with very vexing EGR problems before the machines were installed to even produce the motor, but was not only past the point of no return, there was no available point to return to, other than shifting priorities to delay the 4.5L baby Power Stroke that was supposed to come out before the 6.0L, and extending the 7.3L a little longer).

2002 is a strange model year. I've seen 2002 models with old style grab handle on the passenger side A pillar only, and 2002 models with new style grab handles on both driver's and passenger side A pillars. And I know that the 2002 models I've seen with both driver's and passenger side longer grab handles were not added after the fact by previous owners, because I saw them being installed on the KTP plant floor, for 2002 models.

So many different details between plants and production dates during calendar year 2002... I often add an "-ish" to model years in that range. Like the switch from coarse threaded 14 x 2.0 mm wheel studs to 14 x 1.5 mm wheel studs. Not sure what production date that switch occurred at which plant... but by and by, all models newer than 2002 had the finer threaded studs. But maybe some 2002 models had the newer studs too. That kind of thing.

 

My truck is an 8/02 build and it's from the original owner family. A friend's truck is a 10/02 build bought as a cab and chassis and it doesn't have the valve but has the vacum hose.
Thanks to all for the info, just getting to know the particulars on this vehicle.

 

Y2KW57, Thats funny you mentioned wheels studs as just replaced my hubs a couple weeks ago and mine has the course (2mm) thread pitch and most of the research kept saying I should have had the fine 1.5mm pitch. I guess is just one of those mid year deals and for what it may be worth I believe it was a Kentucky truck per the original windshield sticker when I got it in 2006. I will have to check the build date.
Thanks for the extra info.

 

That’s funny how it’s called the “Ranger valve mod” when in reality it came stock on later model year Super Duties too.

 

Technically the ranger valve is a totally different style. It goes in line with both hoses. Not just the one like the superduty one.