Well yet is another heating problem. So as this winter begins i find myself without any heat in my max. When I was getting the oil changed, my mechanic told me that my radiator fans weren't turning off and that is probably the reason i am not getting good heat. Has anyone else had this problem? Is this an electrical problem do you think? Is my engine going to overheat so the fans have to stay on? Or do I just need to replace my thermostat? Sorry for all the questions at once.... but its too **** cold here. Thanks All!

 

If the temp gauge reads cold than you need to replace the t-stat.

The electric fans run when the defroster is on, so turn the defrost off and see if the fans turn off.

 

The temp always stays right in the middle, and the defroster isn't on when this happens.

 

1. Fan relay ? stuck. Most probably no relation to cabin heat.

2. No good cabin fluid circ, or engine thermostat bad [= engine temp low].

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See Maxima.org:
http://forums.maxima.org/showthread....=1#post3499240
http://forums.maxima.org/showthread.php?t=361759
http://forums.maxima.org/showthread.php?t=362106
http://forums.maxima.org/showthread.php?t=363118
http://forums.maxima.org/showthread.php?t=360258



How it works: Engine water circulates always in cylinder heads and cabin cell tubings, if temp ctrl lever =valve open. This water is cold until engine really warms. Now you start to get hot water.

Next the thermostat opens and engine water will be cooled in the front radiator. When the radiator cannot cool the fluid, fans start to operate, via ECU ctrlled relay (or by independent thermostat elements on radiator side)
However, If the engine thermostat is stuck open, the engine stays always cool and cabin heater will never get hot (lukewarm, yes).

Engine water circ heats the Cabin heatercell, and air blower sucks outside air through it and results in air cooling the cell. If the incoming waterflow from engine is insufficinet or temp is low, the air will never become hot. Revving engine revs the pump also, you get more excess heat and watercirc and so more warm air in.

Cabin heater valve is electronically controlled, vacuum powered valve inside engine compartment. Its located on engine bay wall, under the hood. It gets it operating pover via vacuum tubes from engine(check if leaking). It is electrically controlled (check its coil resistance and that it gets its control voltage). Open and check that it is mechanically operative.