Fan speed rheostat question.

[CMF_micra-man]

I think I remember reading in the old forums that the failure of the fan speed rheostat is a common problem with Micras.

My fan for the heater/air conditioner only works on FULL speed, the highest setting.

I replaced my rheostat less that a year ago and the local Nissan dealer was happy to replace it under warranty... however they feel it failing inside warranty may be a sign of other issues. Perhaps something like the fan motor drawing too much power because the bearings are failing.

When they quickly tested the current draw on the fan motor they found nothing wrong.

And now they don't want to replace the rheostat until they keep my car for a whole day and investigate things further.

I am concerned they will "find" an issue in order to recover their costs for investigation. BTW, a new fan motor is over A$500.

Could a few people confirm that failing rheostats are a common problem with Micras (if that is the case) and if there are any other websites that make reference to this issue I would appreciate their URL.

TIA

 

[CMF_makes]

Hi Micra-man, yes I believe this is a well known problem.

Both myself and "no jamming" have experienced this on our micras. The aircon/heater fan only working on the fastest speed option on the control.

A fair while ago I actually bought a brand new resistor (reostat ?) module from the Nissan dealer for about $40. The even had it in stock on the shelf (which would indicate it is a commonly requested part ? ).

This fixed the problem for me for a while but then it failed again.... So I also suspect it may be getting "burnt-out" for some reason.

I haven't really investigated any further at this stage... I will let you know if I come up with something. Please let us know if you discover a possible solution. Thanks

 

[CMF_NotAnotherSSS]

They arent a complicated device, mabye someone with some electronics experience and time could figure out putting some new resistors on the PCB? Fan speeds would change slightly but if you could use some higher quality parts mabye it would last a bit longer?

I'd be willing to look at it if I ever had the problem.

Mind you, $40 for an electrical part from a Ni$$an $tealer$ship is pretty reasonable!

 

[CMF_hi3cmz]

Yap, heater fan resistor fail often and letting one or more motor speed down, the blower motor also need to check, recently I tood off blower motor and disamssembled it, and found out that inside the motor is so messy, the carbon is wearing out and I don't wanna spend time to find them, so I decided to replace the motor + blades. After swap the new blower runs much quiet and smooth.

Fan resistor in Taiwan is about the same price than AU, the motor assembly is about USD$70 (OEM) with blades or $50 without (white brand). Hope this helps.

 

[CMF_nz_aj]

From what I've seen the various Nissans (March, Pulsar, Bluebird etc) all use the same concept, a card or similar with "resistors" cooled by the fan airflow. I've only seen two different card type styles (& one heatsink type). When they blow, it's possible to scratch off some insulation & drop some solder onto the broken area. This gets it going again.
In a reasonably late model nissan with climate control, I've seen used a multi pinned heatsink version. I guess this is the answer, maybe some retrofit can be made?

 

[CMF_hi3cmz]

The newer Micra (2002+)uses much smaller fan resistor, seens like they are using new material to do the job, might improve durability, I don't know if older k11 can use it, when time come for mine, I will figure it out...