HVAC heat blows warm/hot on drivers side, cool/cold passenger side (warranty issue)

[Fummins]

I'd let the dealer do it if you have warranty. Although I'd do it myself if it were mine, I'm always able to find a loose or missing bolt when I look over work done by shops or dealers.

[Top_Fuel]

Hmmm...

[Fummins]

Learn something new everyday!

[01-7700]

I made an appointment for a $99 diagnostic at my local Mitsubishi dealer. The service manager starting telling me all the reasons why it could be my fault that the heater isn't working. I should get my borescope before the appt. what should I document before going as to avoid getting ripped off?

[pilchardfish]

That is hugely helpful Pilchardfish! Thank you for posting that information. Now we know what the issues is, and we'll just have to come up with our own solution (for those of us not under warranty).

I agree, seeing a TSB or something would also be very helpful. Did you get any documentation with your warranty work that may be helpful to us?

Only thing I'm unsure of is whether Mitsubishi admit it's a known fault; or if it's just that the dealer themselves have seen so many that it's a known issue to them hah. Apparently the other week they had two Mirages in both with dashboards out at the same time.

This past few weeks, I've not been able to get the cabin anywhere near "hot" in the recent cold snap we've had. Dealer did say it's strange I hadn't noticed it sooner; however unless it's freezing, I only ever have the heater on warm. Past couple of winters have been quite average, nothing too extreme.

I'm not due to have it in the workshop for a couple of weeks due to work commitments I've got to work around; but if I find out any more after the work's done, I'll share it

Good luck working on a solution, and hope you find a TSB.

[Daox]

When you go in, could you ask for more details? There are a bunch of us that will be having to fix this out of warranty, and any help would be very welcome. If its a heater core problem, or the plastic shroud, or flapper valves, etc. The more direction and information we can get the better. You've already shed a ton of light on it, and that is much appreciated!

[pilchardfish]

I'm thinking the heater matrix is the airbox that has the flappers and holds the heater core, evaporator, and PTC heater.

Hey. I think it's the part you discuss earlier in the thread, the "heat core", with the combs of metal through which the air is pulled and heated. Not the entire heater / control unit; just the bit that looks like a radiator.

Different country, different terms Fender / bonnet, Trunk / boot scenario ...

[pilchardfish]

When you go in, could you ask for more details? There are a bunch of us that will be having to fix this out of warranty, and any help would be very welcome. If its a heater core problem, or the plastic shroud, or flapper valves, etc. The more direction and information we can get the better. You've already shed a ton of light on it, and that is much appreciated!

Absolutely, no problem. I'll try and find out more detail and will post back later in the month .

[Top_Fuel]

When you go in, could you ask for more details?
You've already shed a ton of light on it, and that is much appreciated!

Yeah...this is great info for sure!

Based on what pilchardfish is saying, it sounds like this could be one of those issues that everyone needs to look out for (rear alignment, anyone? ). I'm going to start monitoring my situation more closely and make sure the dealer documents my concern BEFORE my bumper to bumper warranty expires.

If the heater core AND evaporator have to come out of the car to swap the heater core, this job will be a pain in the butt for a DIY repair.

[Eggman]

It would be good to know if the corrosion is on the inside or outside of the heater matrix / core.

Thanks pilchardfish!