my heat dosent work some one plz help

[safe alattabi]

my heat recently stopped working instanly i changed my thermostat flushed both my radiator and my heater core and put new coolent in my 1995 q45 and i still have no heat and i live in michigan and its so cold out now plz help me out

[Jesda]

Stopped working before or after you worked on your cooling system?

[safe alattabi]

before

[Q45tech]

On 94-96 Q the usual problem is a broken heat mix door acculator [small motor turns an arm when positions door and] mixes in level of heat.

[elwesso]

On 94-96 Q the usual problem is a broken heat mix door acculator [small motor turns an arm when positions door and] mixes in level of heat.

indeed

welcome to NICO. check out the INFINITI ARTICLES section we have an article about fixing this yourself.

[safe alattabi]

i would try to do it my self but i would rather take it in to the dealer ship to do it what is the percentage out of a hundred it is the broken heat mix door acculator and do you recomend me take it in to a pro to do it or should i do it my self

[maxnix]

Depends on youyr budget vs. time requirements. Think it books out in the 10 hr. range.

[elwesso]

i would try to do it my self but i would rather take it in to the dealer ship to do it what is the percentage out of a hundred it is the broken heat mix door acculator and do you recomend me take it in to a pro to do it or should i do it my self

you shoudl do it yourself because with our article you can fix it cheaply and easily.... The dealer labor like brian said is gonna be around 10 hours at least...

[callsnputs]

On 94-96 Q the usual problem is a broken heat mix door acculator [small motor turns an arm when positions door and] mixes in level of heat.

I have a '93 Q45, does the same diagnosis apply? Would the article referenced apply to my model year as well? or are the models significantly differant?

[elwesso]

93s are probably closer to 94s... so id say it could apply...

[safe alattabi]

i took the car into the delaer and they wanted to take 950.00 to diagnose wat the problem is so is it for sure the heat mix door acculator [small motor turns an arm when positions door and] mixes in level of heat.

[elwesso]

Just test the heater mix doors via the climate controller.... that will tell you whats wrong...

[louiegz]

I have a question about this heater mix door. Is this the door that directs the air from the vents to the floor and visa versa? If it is, then you're still could be getting hot air coming out of the top vents. The question for safe alattabi is... Are you getting heat at all or are you just not getting heat on the floor? At least that's the way I understood the question.
Modified by louiegz at 11:57 AM 10/25/2006

[safe alattabi]

im not getting heat at all,

I have a question about this heater mix door. Is this the door that directs the air from the vents to the floor and visa versa? If it is, then you're still could be getting hot air coming out of the top vents. The question for safe alattabi is… Are you getting heat at all or are you just not getting heat on the floor? At least that's the way I understood the question.

its cool air hat blows out of the vents

[louiegz]

im not getting heat at all, its cool air hat blows out of the vents

So when you direct air to the floor it's coming out in the floor and when you direct it to the vents it's coming out in the vents? I never had a problem with my heat in the Q, but when my heat didn't work in a Cavalier I use to have, it was the heater core. I don't know. I'm not one of the experts here.

[elwesso]

since the Q has automatic climate control, theres various motors and things so that a certain amount of air can pass through the heater core... it makes it so the computer can automatically make the temp of the air coming out of the vent as it should be... with the AC on, air doesnt go past the heater core..

[callsnputs]

a question, my buddy has a BMW M3 that had a similar problem. When he got to the bottom of it the issue was the Sensor that tells the car what the ambient temp. was in the cabin so the computer knew to put out more hot or more cold.

I would assume the q45 has something similar, in your opinion is it more likely a door issue or a sensor issue? What have you seen as the more common problem?

Where is a good place to get a Repair Manual, like the Hayes series?

[maxnix]

No Hayes.

http://www.phatg20.com has some online, but for themanual and all the TSB, a one day subscription to

http://www.nissan-techinfo.com/infiniti/ is cheap.

[louiegz]

since the Q has automatic climate control, theres various motors and things so that a certain amount of air can pass through the heater core... it makes it so the computer can automatically make the temp of the air coming out of the vent as it should be... with the AC on, air doesnt go past the heater core..

So this has nothing to do with the door that diverts the air from vents to floor? I was testing to verify that I could get hot air to come out of the vents, and they do. So these are other doors that you are talking about.

[Q45tech]

The failure of the mix door rod or arm is very common on 94-96 thanks to a redesign and substituting plastic for metal [90-93].

Caused from not cycling [weekly/monthly] the system to ac and heat and ac in winter.......grease/dirt in air system makes the door seal tacky/sticky and the rod is weaker than the sealing action and motor is strong enough to damage something when the door doesn't give.

One always uses the built in HVAC diagnostic computer to run all the system tests before tearing into the dash. They buit in expensive circuitry so you could zero in fast.

[safe alattabi]

One always uses the built in HVAC diagnostic computer to run all the system tests before tearing into the dash. They buit in expensive circuitry so you could zero in fast.

how do i do that ?

[goody90q45]

how do i do that ?

Download a copy of the FSM here:

http://www.phatg20.net/modules...id=62

YOu need to follow the self diagnosis instructions in the HA (Heater and Air Conditioner) section of the FSM. It's long and drawn out, with no tools required, sitting in the driver's seat, and you need to follow the steps by the letter. When you complete the test the error code (faulty heater door) will be displayed on your heater display.

The self diagnosis features throughout this car are what makes it so unique and is one of the contributors to the Q's original high sticker price. Read the HA chapter and take advantage of it.

[Q45tech]

The faulty heater door may not show up because the rod break may be after the position sensor ...............the motor turns and the sensor reports the change in motor position.........just that the rod is broken.

What the diagnostic tells you is all the temperature sensors are fine and other things to rule out first before pulling the dash apart.

[louiegz]

The failure of the mix door rod or arm is very common on 94-96 thanks to a redesign and substituting plastic for metal [90-93].

Caused from not cycling [weekly/monthly] the system to ac and heat and ac in winter.......grease/dirt in air system makes the door seal tacky/sticky and the rod is weaker than the sealing action and motor is strong enough to damage something when the door doesn't give.

Yea, I leave my climate control on auto all year, most of the time. Even in the winter, you park your car some place sunny and it clicks the A/C on for a bit, always cycling the door year round. I must admit that in the summer, I don't cycle it, so I should get into the habit of doing this so I don't have a problem with that mix door. That would realy suck to have to spend all that mony to do that.

I still don't realy understand why if it's just the mix door that safe alattabi might be having problems with, that why there isn't heat coming out of the vents. From my unexpert opinion, I think it's more that that.

Hey safe alattabi, did you check if that mix door is working? you know you can hear it with a slight thud when it switches over. Not only that, you can feel where the air is coming from. Check that and rule it out.

[Q45tech]

There are multiple mix and diversion doors moving look at diagrams in FSM.

The mix door is not all or nothing as you can have heat [% or warm air and % of ac air combining at the same time...............necessary to get 1F resolution...[mix door probably has 25 positions............plus the recirculate/fresh air door plus the various doors to direct air thru various positional outlets.

When the build in diagnostics shows no problem you then tear the dash apart and find a broken plastic arm or rod.............the assembly must be taken totally apart to replace the door..............some have found methods to patch sleve repair the rod.

We won't take short cuts because of our 12 month warranty on repairs way too much risk for a business to take.

[louiegz]

Oh, now I understand. Thanks Dennis. Looks like they came up with an overly complex system under that hard to reach dash to direct the air.

[Q45tech]

Much less complex than newer automatic temperature control designs.

The problem is with 60k warranty they only design them to last twice that long.

Who can fault a car or supplier that lasts twice as long as the warranty certainly not the new car buyer [the bulk of which dump at 60k] and high repair costs become known and reduce the resale prices which helps used buyers afford the used lux vehicle.

The problem is used buyers don't realize that to keep the COMPLEX systems functioning as new will cost them.

A cars true long term durability is reflected in the 90% loss of value a 10 year old car sells for [corrected for a 30% loss of dollar value due to inflation].

A MSRP $50K in 1994 car sells today for $4k [which is really $2800 in 1994 dollars].

[elwesso]

In the "4" menu on the diagnostics it tests all of hte mix door positions...

I have an article how to do the self diagnosis, it should be posted up on NICO soon!

[Q45tech]

Think you are missing the FACT that the mix door MOTOR and the mix door position sensor are in the same assembly. The Mix door sensor measures the position of the driving motor not the actual position of the mix door.

When things break AFTER the dual assembly the diagnostic says ok because the motor moves not because the door moves!

[safe alattabi]

In the "4" menu on the diagnostics it tests all of hte mix door positions...

I have an article how to do the self diagnosis, it should be posted up on NICO soon!

how soon????????????