my 98 is doing the same....actually vents at idle and def when
accelerating....i've been told i have a leak / crack in the vacuum can
under the wiper cowl. don't know if the 02 is the same
bob
On Sun, Oct 17, 2010 at 5:08 PM, jon@dakota-truck.net wrote:
> SilverEightynine@aol.com wrote:
>
>> Anyone have any insight to the heater/AC controls for the selector
>> switch
>> (floor/ panel defrost etc) on a 2002? Co-worker of mine seems to
>> have trouble
>> with his truck, and I don't know if the later Gen IIIs still used
>> vacuum
>> controls or of they are electronic. His HVAC system is stuck on
>> window defrost
>> and he can't get it to switch to any of the other positions. (dial
>> works, but
>> nothing changes)
>
>
> Gary is correct, the controls are electronic. It looks like the
> AC/heater control in the dash is actually the brains of the climate
> control system. The FSM treats it like a black box, saying that
> nothing except the panel lights in it are servicable. Although I
> can't be certain, it looks like it may have some microcontroller or
> other logic circuitry in it as opposed to just being simple rheostats
> and such. One of the lines running into it is for the PCI bus so I
> imagine there is a computer of some sort in there. Looks like almost
> all of the diagnostic testing that you can do with it requires a
> DRB III.
>
> At any rate, from what I can gather, it looks like the mode selector
> switch operates on the principle that as you go from the far left
> (recirculate?) to the far right (defrost), the resistance goes up a
> bit more as you hit each position. Must be something in the control
> module that can read this resistance to tell which position you want.
> So, possibly the rotary switch/rheostat mode selector switch itself is
> bad, or possibly something else got fried in there. It might not hurt
> to see if it can be dissasembled to see if you notice anything obvious
> like a broken circuit board trace or something physically wrong with
> the switch.
>
> If you can get your hands on another control module to try it, that
> might be worth a shot. Looks like a new one sells for around $230, so
> maybe eBay or the salvage yards would be the way to go. Looks like
> there are at least a couple of different versions, depending on
> whether the truck has a rear defroster or not.
>
> --
> -Jon-
>
> .- Jon Steiger -- jon@dakota-truck.net or jon@jonsteiger.com -.
> | '96 Kolb Firefly, '96 Suzuki Intruder, Miscellaneous Mopars |
> `-------------------------------- http://www.jonsteiger.com --'
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