2006 f-350 4x4

clean one · 07-02-2009, 07:33 PM

I just bought this truck i noticed today when i turn the 4X4 switch to high or 4X4 low in a few seconds the A/C starts blowing out of the defroster. Is this normal, this is my first 4x4 and first diesel

Thank You

taz4x4150 · 07-02-2009, 08:59 PM

My first impulse would be that they are both vacuum feeds and that they have a common line somewhere. Just a wild thought, otherwise I'm as lost as you! GOOD LUCK!

canuck623 · 07-02-2009, 10:13 PM

The vacuum solenoids are near the right fender. There is a vacuum harness that runs to the wheels. You have a leak somewhere between the solenoids and the hubs. Pull the vacuum lines off at the hubs and plug them. Try the AC again when you ask for 4X4. If it works ok it's the hubs. If it still goes to defrost you have a leak somewhere in between. Just have to trace it down.

clean one · 07-03-2009, 02:04 PM

I drove it around the block today with it in 4x4 and the air started blowing back out of the vents. I will check for leaks like you said. I need to get me a owners manual there wasn't one in the truck. How can i tell if the 4x4 does work , jack up a tire or something.

Thanks for the great help

Ades

ghostriderr6 · 07-03-2009, 02:15 PM

i have an 05 excursion V10 and 1 out 10 times i put it in 4WD it does the same thing, my a/c switches from the vents to the defrost ducts but it only lasts a minute or so and it goes back to normal

canuck623 · 07-03-2009, 06:51 PM

If it only happens for a short time then starts working again it's probably because you have a small leak at the hub seals and the reservoir doesn't have enough reserve. Once the hubs are in 4X4 and sealed up the vacuum will return.

canuck623 · 07-03-2009, 06:54 PM

Quote:

Originally Posted by clean one

I drove it around the block today with it in 4x4 and the air started blowing back out of the vents. I will check for leaks like you said. I need to get me a owners manual there wasn't one in the truck. How can i tell if the 4x4 does work , jack up a tire or something.

Thanks for the great help

Ades

If you have a vacuum pump you can jack the wheels off the ground and apply vacuum to the hub while turning the wheel. If it clicks in and the front axle turns it's working. You can do the same thing with the engine vacuum it's just easier if you can be there as you apply the vacuum to the hub.

clean one · 07-05-2009, 10:24 AM

Ok thanks for the advice i will try that. Looking under this it looks like it has never been off road, because there is no dirt , mud of any kind any where . There is some places you just can't wash off. And it is CLEAN all over underneath. So maybe they haven't been used much.