Has anyone done one yet and how bad of a Job IS IT? Thanks...
Kind of not looking Forward to IT! LoL

I have not done the job, but I think the dash needs to be taken apart. What part of the country are you in? Instead of replacing the heater core, you could do the hose bypass under the hood if you can live without heat in the car's cabin.

My heater core is not leaking, but one or more of my the small modules that move the various air pathway doors under the dash are broken. So I have ac but no heat. I can do without it since I live in Phoenix. I think I can find the modules on ebay or at a junk yard, but I am afraid to tear the dash apart just to restore heat that I can live without.

I am in South Georgia and it does get pretty cold here being that I am from South Florida. But yes it's by passed now...

I just changed mine last night without removing the dash. Took bout an hour

Page 15 of the HA section of the FSM shows a diagram of the heating unit and cooling unit. The diagram says "it is necessary to remove instrument panel" to access either the heating unit or cooling unit. You must have found a way around that. With the method you used, would you be able to access the bilevel door motor or the blend door motor? My heat does not work and the diagnostic says the problem is with the bilevel door motor and blend door motor. I have not tried to find the parts because I figured the replacement work would be too much for me.

my12by60 wrote:Page 15 of the HA section of the FSM shows a diagram of the heating unit and cooling unit. The diagram says "it is necessary to remove instrument panel" to access either the heating unit or cooling unit. You must have found a way around that. With the method you used, would you be able to access the bilevel door motor or the blend door motor? My heat does not work and the diagnostic says the problem is with the bilevel door motor and blend door motor. I have not tried to find the parts because I figured the replacement work would be too much for me.

Unfortunately no. The way I did it was I dropped the glove box then removed the evaporator box. Once you do that you can see the side of the heater core and you can get to the tubes. Then you remove the screws from the heater core, twist then then pull them out. Then slide the heater core out. The tricky part is putting the spring back on the the open and close valve on the top tube.

Ok. Thanks for the explanation. Good info for those that need to replace the heater core.

I have yet to read of anybody here that has torn things down to heating and cooling units for repairs. Maybe somebody will chime in one of these days.

Claycoboi wrote: ↑

Thu Dec 22, 2016 3:43 pm

my12by60 wrote:Page 15 of the HA section of the FSM shows a diagram of the heating unit and cooling unit. The diagram says "it is necessary to remove instrument panel" to access either the heating unit or cooling unit. You must have found a way around that. With the method you used, would you be able to access the bilevel door motor or the blend door motor? My heat does not work and the diagnostic says the problem is with the bilevel door motor and blend door motor. I have not tried to find the parts because I figured the replacement work would be too much for me.

Unfortunately no. The way I did it was I dropped the glove box then removed the evaporator box. Once you do that you can see the side of the heater core and you can get to the tubes. Then you remove the screws from the heater core, twist then then pull them out. Then slide the heater core out. The tricky part is putting the spring back on the the open and close valve on the top tube.

No offense to anyone here, but if you try this method you are a fool. And who was the fool that tried it on my 79k 1999 Q45t? Me. I tried removing the evaporator box and it essentially crumbled and the heatercore is visible but I see no humanly way possible that it can come out without removing the dashboard like the FSM says.

So now I have to make the choice to either junk this lovely car or take the rest of the summer trying to install a new heater core and evaporator core box. In short, take no shortcuts and follow the FSM.

my12by60 wrote: ↑

Thu Dec 22, 2016 5:01 pm

Ok. Thanks for the explanation. Good info for those that need to replace the heater core.

I have yet to read of anybody here that has torn things down to heating and cooling units for repairs. Maybe somebody will chime in one of these days.

I'll let you know if I decide to go through with this repair, it's just that I'm ultra short on time and have way too many projects to take this on. Sux because this car is such low mileage and is a beauty...oy

Hello...is the person or persons who wrote this article still participating here? I’m particularly curious about the guy who removed the heater core without removing the dashboard lol.

Because I’m now for the 2nd time, going to be removing the dash to get to this. I’ve finally got all tools, parts and TIME and SPARE MONEY that I’ve needed to take 3-5 days off to fix lol.

UPDATE: I have a miracle to report lol.

So i couldn't bear the thought of having to take off the dashboard again (along with the steering wheel airbags and all that s***). Especially considering I did all that few months ago and ended up with nowhere. So I just decided to see for myself how far I could get if I just dropped the glove compartment, took the screws off the little bar and pull the evaporator box.

The evaporator came out like a breeze. 4 or 5 screws and a little bit of wiggling to do, but once I moved that bar it practically just dropped down with the whole unit. I don't understand how the person who crumbled theirs happened.

Then the heater core, even though it wasn't right behind the evap like I thought, i did have a clear view. That was a slight b**** to remove, because I had no access. So I went ahead and unscrewed the 8 screws for the tubes, cut the stupid unnecessary plastic holder piece that was in the way, and slid it out.

Getting the new OEM heater core back in did require the same technique (I'm being careful not to break or force anything unless I don't need it). But I dappled some adhesive to my screwdriver to hold a couple of nails that are in tight spots.

It's definitely not a 1 hour job (maybe now that I know), but it's saved me a whole day of work. It still took all night and i have to change out the evap tomorrow, but I am just absolutely floored that I could do it this way. I called infiniti just to see what they would say, they wanted over $800, quoting removing the dashboard like the manual says. That's definitely not necessary.

But I must say: there's a chance the previous owners may have changed the evaporator. If there's something missing that I don't know about: It almost seems like something was cut. Like a metal piece. And I've seen on YouTube where someone suggested cutting a bar on a different make to avoid pulling the dashboard.

At the same time I'm low key mad because I did previously do the dash removal and got nowhere not realizing the air con had to be recovered and I didn't have the whole heater core part with tubes (and it looks as the heater core was never leaking, it was the f*** plastic tubes which were disintegrating based on the chalky old coolant caking them).

Regardless, this is such a relief! While I'm at it I'm changing evaporator and cleaning twigs and leaves that have stopped up my blower motor. That's why I tell my friends: I don't need a new car, I just need the time and patience to work on the one I have.

I'm glad you're making progress!

Q451990 wrote: ↑

Fri Jan 17, 2020 8:37 am

I'm glad you're making progress!

I have to say though the positions I had to get in were...creative lol.

Even though the service manual is BS for making us remove the dashboard, I think they write it more to save a service technicians neck and back versus getting things done quicker.

I'm going to resurrect this thread yet again. I'm now facing the same issue. AC works great. Won't heat. I hear it trying to work but no joy. I'm seeing codes 25 (sunload sensor) and 27 (bi-level door) when I run the diagnostics. My question is... I don't mind taking apart the dash to a certain degree. I do NOT want to tinker with the air bag. Do you think I could get down to the heater core by taking apart the center console and possibly removing the radio and AC controls? I want to verify what's broken before I start ordering parts.

Sapofeo wrote: ↑

Tue Sep 21, 2021 10:20 am

I'm going to resurrect this thread yet again. I'm now facing the same issue. AC works great. Won't heat. I hear it trying to work but no joy. I'm seeing codes 25 (sunload sensor) and 27 (bi-level door) when I run the diagnostics. My question is... I don't mind taking apart the dash to a certain degree. I do NOT want to tinker with the air bag. Do you think I could get down to the heater core by taking apart the center console and possibly removing the radio and AC controls? I want to verify what's broken before I start ordering parts.

Lol no, don't! I would first check near the drivers side
Where the pedal is: this was my first issue of heat not working originally. There's a motor there that controls the door for the a/c and heater core. Especially since you're getting a code for bi-level part. (Btw what scanner you're using that's able to read that?).

The motor you need is a dealer only part, you may need: Infiniti 27732-70F00 Air Mix Actuator Assembly.

If it is your heater core, you can't get thru via the radio controls area. Don't even waste time. The easiest way is to drop glove box as if changing cabin air filter, remove evaporator box (has to be done partially from the 2 connecting lines at the firewall). Then you just reach up and unscrew the plastic lines from the heater core.

But for the sake of preserving your air conditioning, I just wouldn't do it yet. Have to change the o rings and the drier, and pay for an evac/recharge. Took 5 months after replacement to get it working right again because of either not changing the drier or someone overcharging it. Never want to do that s*** again.

Also: my heater core never stopped "working" or getting hot, I had to replace mine because the plastic tubing was leaking down under the passenger side carpet. All the while, it still has heat.

98_Q45 wrote: ↑

Tue Sep 28, 2021 9:29 am

Sapofeo wrote: ↑

Tue Sep 21, 2021 10:20 am

I'm going to resurrect this thread yet again. I'm now facing the same issue. AC works great. Won't heat. I hear it trying to work but no joy. I'm seeing codes 25 (sunload sensor) and 27 (bi-level door) when I run the diagnostics. My question is... I don't mind taking apart the dash to a certain degree. I do NOT want to tinker with the air bag. Do you think I could get down to the heater core by taking apart the center console and possibly removing the radio and AC controls? I want to verify what's broken before I start ordering parts.

Lol no, don't! I would first check near the drivers side
Where the pedal is: this was my first issue of heat not working originally. There's a motor there that controls the door for the a/c and heater core. Especially since you're getting a code for bi-level part. (Btw what scanner you're using that's able to read that?).

The motor you need is a dealer only part, you may need: Infiniti 27732-70F00 Air Mix Actuator Assembly.

If it is your heater core, you can't get thru via the radio controls area. Don't even waste time. The easiest way is to drop glove box as if changing cabin air filter, remove evaporator box (has to be done partially from the 2 connecting lines at the firewall). Then you just reach up and unscrew the plastic lines from the heater core.

But for the sake of preserving your air conditioning, I just wouldn't do it yet. Have to change the o rings and the drier, and pay for an evac/recharge. Took 5 months after replacement to get it working right again because of either not changing the drier or someone overcharging it. Never want to do that s*** again.

Also: my heater core never stopped "working" or getting hot, I had to replace mine because the plastic tubing was leaking down under the passenger side carpet. All the while, it still has heat.

Well, I removed the center console and radio (I had done this once already to install the bluetooth adapter to the radio). Took like 10 minutes. Learned quickly it was a dead end. hahah. As far as the scanning goes, I used the built-in diagnostic described on HA-29 in the FSM. It spit out the two codes I listed above. I completely agree with not risking the AC. I have the luxury of having another vehicle with a working heater for cold weather transportation. I'll see if I can access the motor door by the gas pedal. I really appreciate the information, thank you.

I checked the motor by the gas pedal. When I move the temp dial, I do see it moving, so I know it's not the motor. I suppose it could be the physical door that's broken but that seems unlikely. I'm assuming the problem you had was the it wasn't moving that arm right?

Right, mine wasn’t moving at all. I actually got a quick fix by unplugging it and cleaning the linkages. But it worked for a day and stopped again lol. Are you certain it’s moving fully? Are you getting any heat?

I’m trying to think: I know with the evap box removed, you can see the flap that opens and closes to direct the heater core or the evaporator core. But obviously you don’t want to do that, yet. What you might be able to do is drop the glove box, see if you can hear that door moving. I think the one that wasn’t working for me, was called the air mix motor. There’s another one that might be connected to control the evap core/heater core flap. Don’t quote me, but you “might” actually be able to reach that by removing the airbag on the dashboard. There’s another lever up there that looks like the air mix motor.

I know this looks complicated, but there’s a hands full of motors in there. But I think only 2 control heat and a/c.

I took a video of what I'm seeing. The gears are moving and it's definitely pushing that post that goes towards the passenger side. I'll likely need to see what it's doing at the other end.

https://i.imgur.com/VUs93VG.mp4

I think the bi level motor is going to be on the passenger side, up into the dash area. Unfortunately you can’t see the door itself unless you remove the evaporator box (no need to remove dashboard if you ever do).

Just want to be sure: your heater hoses are connected right? Obviously won’t work if it’s been by-passed.

I've not bypassed anything. I'm down to the evaporator box. Haven't quite figured out how to get that thing out. I found 4 bolts so far. You mentioned there may have been a 5th. I'm going to see if I can find something in the FSM showing how to remove it. I took out the three screws holding the top and bottom together. I'm wiggling but it looks like the evaporator is moving too. I gotta be missing something.

Hey!

I know this is painfully slow trying to get tips in the middle of a project lol. I been busy myself.

Anyhow: you CAN'T remove the evap box UNLESS the 2 bolts for each H and L pressure hose is removed. Which is why i say don't bother because that'll require evacuating your refrigerant (and getting a new drier, o rings for both hoses, and paying $79-129 for a recharge). There's 4 or 5 bolts around the evap box, but it won't detach until you remove the lines.

If you don't have heat, I highly doubt it's because of your actual heater core. You want to find the motor. Even a leaking heater core will produce heat (I know because I had the unfortunate fate of the plastic hoses going bad the 1st time, and then the actual NEW infiniti heater core going bad the second time (victim of coolant stop leak products).

I wish I knew what motor it was. But you can likely better access it by removing the passenger side airbag versus the heater core itself. Or even removing the dashboard all together, which doesn't require messing with the a/c box. But don't do that either because it's a royal b****! You should be able to see a motor looking thing somewhere around the passenger side airbag. Adjust your temperature knob from cold to hot and see if there is any movement.

Removing the passenger airbag isn't exactly easy either, but it's also like 4 torx bolts (i got the right socket from home depot). It may give you just enough leverage to see inside of the upper dashboard. But you may just see that motor while you're doing it.

I'm always working on multiple home/auto repair projects so timing really isn't an issue. I've been driving around with the glove box removed for like a week. I come back to it when time permits. There is indeed another motor by the passenger airbag. that's the "intake door motor" for when you hit the recycle air button. It works just fine. The motor by the footwell I believe is the "air mix door motor", which appears to be moving well as well. The one that's invisible is the "bi-level door motor" which appears to be the one that requires removing the entire dashboard.

Sapofeo wrote: ↑

Tue Oct 19, 2021 7:43 am

I'm always working on multiple home/auto repair projects so timing really isn't an issue. I've been driving around with the glove box removed for like a week. I come back to it when time permits. There is indeed another motor by the passenger airbag. that's the "intake door motor" for when you hit the recycle air button. It works just fine. The motor by the footwell I believe is the "air mix door motor", which appears to be moving well as well. The one that's invisible is the "bi-level door motor" which appears to be the one that requires removing the entire dashboard.

Hmm...Idk. Tbh I still think your air mix motor isn't working correctly. You say "appears" to be working well but...is it really? You may even try unhooking the arms and moving it manually to see. It doesn't just "move", but when properly working, that little motor really does a full dance lol. If it's just moving halfway, you may need to clean the arms up. I had that same issue when I first brought mine. There was so much gunk and dirt there, the motor wore out. I even unplugged it and replugged it and it miraculously worked for a day, and then went back stuck in cold mode.

I think bi level door only controls the direction of airflow.