is this fixable or do i need to by a whole new hvac unit

I have bad news and worse news for ya.

The bad news is that yes, you have to buy a whole new HVAC unit to fix it.

The worse news is that at the very least your HVAC controls need the revised gear set

This will help.
https://www.evolutionm.net/forums/ev...ega-guide.html

Haha! I just sold mine... For the record anyone for a lancer works... So ebay it up... And i assume this happen because of the binding door issue so pick up the revied gears setup while youre at it. Also available on ebay

you probably need to go beyond just the revised gears, I too had this issue and had the same year EVO so its like 99% chance your going to need to do the air mixer box repair/ rebuild as well, which is a pain in the a$$, but doable.

if you do the tsb fix, i have one of the parts for sale

You DO NOT need an entire new HVAC unit.

Unless they're currently out of stock, you need the shaft that broke off. You can get one off ebay like I did. Cost me $22.50 shipped.

1 Heater Control Knob - $10 & change (stealership) part number at home, I'll update the part number later. You might not need this if the prongs on the back are still in good shape. Mine broke along with the shaft.
1 MR979515 WIRE $5.44
1 7801A110 HEATER CONTR $16.00 (revised gears)

These last two I purchased from MitsubishiParts.net....charged me $10.95 shipping! Oh well...Russell couldn't do anything about it.

Replacement of the actual broken shaft is a bit tricky. It pops out but there are gears behind it and they have to be remain in the same position or marked accordingly so they go back together exactly the same way. That way you have full temperature range with the new knob. I found out the hard way and went through a trial and error session...and a six pack before getting it just right LOL

I posted this video in the above Mega HVAC thread showing you how to replace the parts I posted above excluding the actual shaft replacement:


Hope this helps you out.

^^^good info. Now I got the some part #'s to fix mine. Broke mine several months ago and just stuck the knob back on and been controlling it from under the dash since.

Welcome to Evo ownership.
I used to adjust mine under the dash @ the cable linkage before I fixed it.

Thanks. Is there a part number for the shaft that broke off?

There is no part number for just the shaft, but you can pick up an aftermarket one here if you don't want to spend the money for a whole new control unit: http://www.ebay.com/itm/02-05-LANCER-03-06-OUTLANDER-Heater-Control-Panel-Switch-Knob-Shaft-/331305021707?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3ALancer&hash=item4d2351710b&vxp=mtr
Hope that helps!

As a follow up, be aware that there is someone selling "professionally cast" shafts on Ebay. They are grey and full of bubbles and will cause you nothing but grief in reinstalling the same stem over and over. What good is their warranty if the stem keeps breaking? Stick to the injection molded type. The seller selling the correct stem is black_mountain_designs. Here is an updated link of where I got mine.

http://www.ebay.com/itm/Mitsubishi-03-05-LANCER-AC-Heater-Control-Panel-Switch-Knob-Shaft-Stem-/331305021707?fits=Make%3AMitsubishi&hash=item4d2351710b&vxp=mtr

I also had the shaft break. Well this shaft also work on a 06 Lancer SE

If it looks like the picture in the first post then yes. I have a 06 Evo and bought one and also bought the gears and cable, even though mine were the newer ones, a new knob and swapped the OEM right hand shaft to the left and used the new one on the right. Did that make sense lol?

Does anybody by chance have a How To tutorial video on how to replace this shaft? Nevermind I found a pretty good one that goes into detail. Here it is to share:
https://youtu.be/d8jNWN6TRzE