Well like anything electronic, it could just go bad at anytime (the HVAC controller). Having it reset might not fix it but if it can be done for cheaper than the part it's worth a try. My shop did say that the DRBIII and StarScan is dealer only stuff (although I remember one thread someone said that their Carmax had the StarScan (I think it was an authorized retailer for new Chryslers).
As far as the gauges dieing just once and the wiper issues, maybe the connector behind the Instrument Cluster is a bit loose. Or (are you ready for it...) the overly generic 'loose ground' connection somewhere. Since all of our trucks use the CANbus system (which essential multiplexes lots of signals from various sensors and switches into much less wiring) good clean ground contacts are very important.
Was the gauge cluster tweaking out around the same time that you started having the HVAC problems?
** Also, when the gauges did flat line, was the entire IC dead (was the odometer and gear selector still lit up?)

 

So it sounds like I need to take a trip to the dealer to see if it can get fixed? If not I'm hoping its just the hvac controller that should fix it? And is the controller the component right behind the ***** and a/c lights?
I just read about the loose ground deal yesterday.. my understanding is that can be fixed with a new fuse box? And the gauges have done that maybe 10 times max in the past year or two, and it has been totally unrelated for the hvac deal. When the gauges went the odometer and gear selector stayed on, and the majority of the time the 4 small gauges would go dead, but I do recall at least once that the tach and speedo went dead as well, and this was at the same time as the other 4 gauges going dead

 

I was browsing thru the part and service manuals and from what I can tell, the only hvac controller is the unit built into the same panel with the controls and *****.
I just found this on google as I was typing your response
http://dodgeram.org/tech/troubleshoot/Problems.htm
Under HVAC and vents changing by their own it talks about 'vacuum leaks', that another common used phrase around here like the loose grounds.
Speaking of grounds, and the fuse box problems... I'm pretty sure the majority of folks that replaced the fuse box due to bad ground issues was for lighting issues (headlights, turn lamps etc.) I'm not sure if the fuse box problem would cause your cluster problem. But there are numerous ground connections on the truck that could cause your problems, or even a loose or partially damaged wire.

** That website seems pretty old, now that I went thru it some more, so not sure how relevant that would be for your '05

 

Ah ok well a local junkyard has a few 3rd gens so maybe I can get a deal there on a controller, if the dealer can't fix it. I was told about the vacuum at first - but I guess that is for the older models, this model is all control by dc motors (with too much torque - and they are apparently notorious for breaking the doors in the hvac system).
I haven't had the instrument cluster go wack for a while so I'm not too concerned about it until it stops.. like the old saying if it ain't broke don't fix it!
Also, the drivers side heat seems a little cooler than the passenger side, at first I thought it was a door issue but now as I research more I understand the heater core could be the problem? Maybe a blockage in part of it so where the fan blows the heat to the drivers side isn't getting good coolant flow?

 

Doing some research, seems a heater core flush would be the next step - any info on that? I understand its just hooking up a garden hose and turning the pressure on gently, and hooking it up so the flow is reversed

 

When I replaced my water pump, I held a garden hose up to one of the hoses going to the heater core for a few minutes. Then I did the same thing on the other hose. I guess that's called a shade tree mechanic heater core flush and reverse flush LOL. I hear they sell kits to fully hook up the garden hose to the heater core hoses... that might eliminate some of the excess water splashing I dealt with, but my method seemed to be pretty effective. I'm sure somewhere out there is a magical product to remove all the buildup and maybe clean it out better - but that might be more hype than what it's worth.

 

Ah ok that's what I figured. I've been reading some other forums and I've heard of people using CLR in their heater core to dissolve deposits, so I picked some up and I read on the back not to use it on aluminum or copper.. do you know if the heater core is aluminum?
Also, I was going to do a complete coolant flush (haven't ever done one) and I guess the method is to drain the radiator, drain the block, remove the thermostat, then stick a garden hose in the top of the radiator and crank it on and let all the goods flow out until its nice clear water. I took the metal twist round cap (my official term for it lol) off the radiator, the coolant was nice and green, but in the little tank (it has the same type of cheesy plastic lid on it that the wiper fluid does so it must not be pressurized?) right next to the wiper fluid the coolant is red-ish and looks dirty... When the flush is done is the coolant added into this plastic tank or back directly into the radiator? And does flushing the system clean out that little tank (I think its called an expansion or overflow tank?). I guess I don't get the purpose of this tank... And I was going to use the prestone coolant - the mix with any coolant stuff but I was reading about some zerez g-05 stuff that some say should only be used in this engine?

Wow that was a lot of questions, I appreciate the info!

 

As the heater core ages it deteriorates and corrodes and gets calcification buildup (might not be proper term). The main problem with using CLR or other products to get rid of the last 6 years of use is it may clean off stuck some stuck on deposits and uncover small holes and then create leaks.
The manual specifies that our trucks use a HOAT only coolant (dealer only mainly) but I think NAPA auto stores sell a HOAT coolant as well for a little bit cheaper. I think it's a pinkish color.
When I did my flush (I replaced the water pump) I drained the radiator and engine block, removed the t-stat. I disconnected all the hoses and just used a garden hose to shoot thru the heater core hoses, thru the engine block in both directions and thru the radiator thru the top only. Some of the bigger hoses made it a messy job because I just used my hands to "seal" the garden hose up. Certainly not a fully pressurized job, but plenty of water made it thru and once it started coming out clean I felt the job was good enough.
That is an overflow tank that you were referring too. Somehow the entire radiator system is pressurized, except for the overflow tank, but the two are connected by a plain rubber hose. Supposedly as the system heats up and cools down the level in the overflow tank will fluctuate. Also if you have a slow leak it will drain the excessive from the overflow tank first before the level in the radiator gets low.
I'm not sure what metal the heater core is made of...

** oh yeah. When you're refilling with new coolant, start with the radiator. Go slow because it may splash out. Once the rad. is completely full fill the overflow tank to the full mark, or about half of the tank. Again top off the rad because it will slowly drain into the engine. Close everything up and let the truck run until the t-stat opens up and coolant is fully circulating. That's when both the upper and lower rad hoses will heat up, also good to have the heat turned on in the truck. When the truck cools down completely check the level in the rad and overflow tank and top off as needed.

 

FYI it is prolly your doors.. My dads truck had the same issues. the doors may seem to be working fine, but did you check to see if the limit tabs are still intact? If not, the motors and doors will not work properly.. i literally just finished up my dads 03 ram this afternoon changing out all of the doors.
http://www.heatertreater.net/Ram%2002-08%20Listing.html <-GREAT ppl with METAL replacement parts. they also include a very detailed instruction book. you DO NOT have to take the entire dash apart to change these. only the surface (the pretty stuff) has to come off. Then a little creative cutting/replacing/taping and you are done. It took me 6 hours to change out all of the doors and everything works fine now.

i recommend you take a look at that site and read up on what they have to say. i tried to call BS on my pops until i actually tore into the truck and noticed that everything that company said was very true. good luck

 

On my o2, I checked my blend doors based on a company that sells replacement doors and provides a video on checking and replacing them. My doors seem fine, however, when checking to see what else may be happening, I noticed the motors didn't turn when I turned the ***** on the dash. I took one on the motors out and supplied 12 volts and it spun with no problem. I'm thinking the control head on the dash may be bad. $160.00 from the dealer. Putting my funds together. I haven't figured out anyway to test the existing control head after removing, so I guess I'm stuck replacing and hoping that fixes it.