Blower only working on setting 4
Cargo Master
Joined: Jun 2010
Posts: 2,113
Likes: 4
From: Iowa
Seeing as you have a diesel I would suspect a vacuum pump issue being the problem with the defrost and possibly the dead battery's.
As far as getting at the fan control switch goes I don't have much experience with Vans, but on the Super duty you can pop the part of dash around the gauge cluster and radio off (the black part of the dash on my truck) exposing the mounting screws to the controls for removal and easy access for diagnosing.
As far as getting at the fan control switch goes I don't have much experience with Vans, but on the Super duty you can pop the part of dash around the gauge cluster and radio off (the black part of the dash on my truck) exposing the mounting screws to the controls for removal and easy access for diagnosing.
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
I'd go ahead and replace the blower resistor. It's the only thing that can cause your blower symptom with a single point of failure. For anything else to take out speeds 1-3 would require two or three simultaneous failures, a far less likely occurrence.
The vacuum motor should be operated only through a circuit that is switched by the ignition, it should not be an always hot feed so it should not be able to drain the batteries if the vehicle is off.
Ironically, I haven't found the vacuum motor in the E-series EVTM so I don't know it's fuse and feed arrangement.
The vacuum motor should be operated only through a circuit that is switched by the ignition, it should not be an always hot feed so it should not be able to drain the batteries if the vehicle is off.
Ironically, I haven't found the vacuum motor in the E-series EVTM so I don't know it's fuse and feed arrangement.
Senior User
Joined: May 2016
Posts: 107
Likes: 0
After pulling and pushing on all electrical and vacuum lines and fiddling with the resistor block a little, all appears to be back to working order. I don't really know what was amiss for awhile, but I gave it good look see today, as well as under the top-of-dash access panel showing the two vacuum operated diverters, and those worked well, along with speed selector switch and function switch. So, touch wood, I'm good to go...Thanks for all the tips and I did learn a lot about how the HVAC works, which is always useful
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Danspeed1
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
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Dec 15, 2009 09:24 PM
