NO AIR

  • Tiny
  • CptTrevor
  • 1999 Nissan Maxima
  • 6 CYL
  • FWD
  • automatic
  • 75,000 miles

My Nissan Max 1999 Heater and Blower unit is not giving out any air. The blower is working on all four. I changed the blend door motor because the first one was not moving. I am having the same problem again it is not moving. I did a continuity test on the line going to the motor and it is ok. When I first put power to it the motor moved in the open position but did not moved back to the close position until I place and external ground on the black wire with the yellow stripe coming from pin 20 0n the back of the control unit. I thought I had it fix so I put the dash back together and now no air is coming out of the system and the blend door is not opening again. There are three wires going to the blend door on the bottom of the white unit the white one with small silver dots on it is hot on ignition, the blue wire with the white strip and the silver dots coming out of the control unit from pin 8 and going to the blend door motor is also hot on ignition- is this correct? The black with yellow stripe and silver dots I think that is ground and that is the one I place an external ground on to close the motor. I would like to know if you can tell me the power sequence of these wires which ones are suppose to hot and from where the power comes from. Also can you provide me a wiring diagram of this unit or where to look for one. Also is there a possibility that the evap could be block and no letting the air blower through. I am in Florida and it is hot with no ac. Thank you for your attention. My telephone number is 12393694324. Any help appreciated. Trevor

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Tuesday, July 19th, 2011 AT 9:32 PM

5 Replies

  • Tiny
  • rivermikerat
  • Member

Try these.

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Tuesday, July 19th, 2011 AT 10:24 PM
  • Tiny
  • CptTrevor
  • Member

How can I try these when I can't read or even enlarge to read the diagrams where can I go to find these because these I can't read so they are no help to me Cpttrevor

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Wednesday, July 20th, 2011 AT 12:42 AM
  • Tiny
  • rivermikerat
  • Member

I'll have to print them out for you and then scan them. Normally our research materials allows us to save copies of images, but not all schematics are allowed to be saved. Like these.

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Wednesday, July 20th, 2011 AT 3:20 AM
  • Tiny
  • CptTrevor
  • Member

Ok when can I expect to received them? Can you provide any help as to why I am not receiving any air through the system or things I could do possibly. I thought I was a very good mechanic until I encountered this system. Why am I having two ignition powers going to the blend door motor? In this case the master control unit is not doing anything. Any position on or off the power is still coming from the back of the master control as long as the ignition is in the on position I don't think this is correct please help Cpttrevor

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Wednesday, July 20th, 2011 AT 3:02 PM
  • Tiny
  • rivermikerat
  • Member

I don't think that you should be seeing battery voltage from two pins. I also don't think you should see battery voltage where you're seeing it with the switch Off. Here are the images I mentioned.

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Wednesday, July 20th, 2011 AT 10:51 PM

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