Mode Switch Modification to run A/C on Defrost

Created: 9/20/2005

Author/source: Dani Benedek

Modifying the mode switch so that the Air Conditioner runs in the Defrost position:

Removing mode switch:

-Remove center console (#100683)

-Remove heat setting knob, mode switch knob, and fan speed knob

-Remove one screw holding AC “Fascia” panel to mounting frame

-Remove AC Fascia panel

-Remove one screw holding mode switch to mounting frame

-Remove the large rubber vacuum hose block from the back of the switch

-Maneuver the mode switch so you can see the 3 wires through the cut out hole that the 3      lights run through[fan fail, lock doors, defrost]

-Either write down, or remember the configuration of the 3 wires and remove them

-Remove the mode switch


Disassembling mode switch for modification:

            Note: Front of the switch=where the knob attaches to

                        Back of the switch=where the vacuum lines attach to

The design of the switch allows it to be assembled only one way, so don’t worry when you disassemble the positioning of the pieces.


-Unscrew the 2 screws that hold the diaphragm assembly to the switch and remove

-Remove the E clip from the shaft in the front of the switch

-Remove the shaft from the mode switch

-push on the front of the shaft while turning the large round white plastic piece in the back (under the diaphragm assembly you just removed). There is a notch on the shaft that corresponds with a slot in the switch assembly, when these align the shaft will push out. This will take a bit of force and I actually had to hammer it softly while turning the shaft. Take care not to lose that little metal ball that holds the switch in the selected position.

-Once you remove the shaft and parts that came with it, set them aside and begin modifying. (See picture)

Modifying the switch:

All I did was cut a small section from a flat male connector, put it in that convenient little slot and soldered it in to the connector as you can see from the picture. My soldering job wasn’t beautiful so I had to file it down a little. I also wanted to spread out the solder as much as I could so it would hold better and reduce the chances of breaking. Take care while soldering, don’t let the connectors in the switch get too hot or you’ll melt the plastic underneath and the studs that hold them down.



This is reverse of how you took it apart. As mentioned above, the switch can only go back together one way with all the notches and ways the parts fit, so it’s impossible to put it back together wrong. Put some grease on the contact surfaces inside before you put it back together. It is easy to strip or crack the plastic while screwing parts together too tight-so be careful. -----Dani Benedek #5003

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