Defrost only
Posting Guru
Joined: May 2004
Posts: 1,366
Likes: 2
From: Northern Utah
Welcome to the FTE
As you are probably aware, the defrost is the default mode for the pneumatically controlled ventilation system. You have a leak which is loosing the pressure and the key is to find the leak. My 03 SD did the same while under warranty (at 35,993 miles) and the leak was easily found at the switch. 10 minute repair.
Good luck
As you are probably aware, the defrost is the default mode for the pneumatically controlled ventilation system. You have a leak which is loosing the pressure and the key is to find the leak. My 03 SD did the same while under warranty (at 35,993 miles) and the leak was easily found at the switch. 10 minute repair.
Good luck
Elder User
Joined: Apr 2004
Posts: 797
Likes: 0
From: Wickenburg, AZ
It'll be a vacuum leak somewhere. The only things on the diesels that are vacuum operated are the climate control and the 4x4 if you have the electronic shift on the fly (ESOF).
I take it that the little vacuum pump does actually run, right? The next place to go is to start tracing lines. I'd trace from the pump on over to the big, black plastic vacuum reservoir first. Then I'd take a look at the lines going to the ESOF solenoid if you have it. The last thing to check would be the line going into the cab for climate control. We have had folks on here run into lines that popped off the switch or more commonly the little vacuum motors under the dash.
I take it that the little vacuum pump does actually run, right? The next place to go is to start tracing lines. I'd trace from the pump on over to the big, black plastic vacuum reservoir first. Then I'd take a look at the lines going to the ESOF solenoid if you have it. The last thing to check would be the line going into the cab for climate control. We have had folks on here run into lines that popped off the switch or more commonly the little vacuum motors under the dash.
