QX4 blower problems

[costlyinfiniti]

1998 infiniti Q4 won't blow heat or air. I checked my ac blower motor and it checked out fine. Went to local parts store and they sold me a blower motor relay. I can't find it to replace it. Does anyone know where this is located. It is not by the blower motor. I removed everything and still no luck. It is supposed to be a easy fix with one phillips screw.

[Toolman5523]

So you checked your blower motor and tested fine, right? Did you check power and ground? How did you check your motor? What led you to diagnose a faulty relay if you have no idea where it is? I mean one of the ways to diag a faulty relay is a "bench test". I'm just asking, take no offense to the questions.

[costlyinfiniti]

I bench tested the motor with 12 volts. It runs. Would love to test this unlocated relay. That is why I am asking if anyone knows where it is located. Can't test what I can't find. Took the advice of the parts man and for $13.34 I bought a relay. Figured I could find it and see if it was the problem. All the posts I have found say it is behind the glove box and it is an easy fix. If the relay does not operate at any of the four speeds it must be shorted out completely giving me no power to the fan.
What do you think? Have you ever dealt with an Infiniti auto hvac system?

[Toolman5523]

No, I have never dealt with any Infiniti auto air, but plenty of Nissan. To be honest I have never had a problem with a "blower motor relay" on any vehicle. So I take it that you have no power to the motor at all, correct. You did check that both fuses are ok? Are you sure you did not misread relay for resistor?

[costlyinfiniti]

I think I can't find this relay because the parts man doesn't know what he is talking about. This has a resister. I am now trying to touble shoot this. (I have it found and removed ) I do not have a good ground on the blower plug. I checked across the plug and have nothing. When I use a different ground I get 13.9 volts. Any ideas if this $200 resister pack (sold only through Nissan) could cause the bad ground?

[Toolman5523]

the switch controls the ground for that circuit. the resistor just adds more of a load to the circuit changing the available volts to the motor. hence the slower speeds. yes, if the main input to the resistor is shot then it could cause a no ground situation. pull your resistor out, and check continuity for all the terminals. you should have varying resistance readings for each setting, but never an open. I sure hope for you it does not cost $200, Nissan's usually run about $30-$40.

[costlyinfiniti]

Ran all the checks and the blower motor resistor is bad. Looks like I'm headed to the dealership to get a new one. Thanks for your help. Maybe I will shop for a 350z while I'm there cause the QX4 is gone before the next timing belt change. ($800 every 60,000 miles) Take Care.

[costlyinfiniti]

It is actually called a "ac fan control amplifier assembly". Dealer only part.

[costlyinfiniti]

FYI
Got the part. $158 after tax. Six screws to remove glovebox and two screws to change the part. Piece of cake. Works perfectly.

[JPeaks]

Originally Posted by costlyinfiniti

FYI
Got the part. $158 after tax. Six screws to remove glovebox and two screws to change the part. Piece of cake. Works perfectly.

Dear Costly:

I read your thread regarding the fan blower problem you had. I believe the same part has gone bad on my 2002 QX4, except my AC fan blows full speed all the time...no matter what controls I adjust to reduce the fan speed. I removed the glove box and found what I think might be the fan control amplifier from your description of your process. Can you give me additional information on what the part looks like? I removed the most noticeable electrical part that has a white plastic cap over five metal fins. I would appreciate any help you might be able to lend.

JPMoore