No heat?

Tiny
NEILB57
  • MEMBER
  • 2000 NISSAN MAXIMA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 160,000 MILES
When the climate control is turned on the AC compressor engages and never turns off. This causes me to get cold air unless I set the control to maximum temp of 85 degrees. The air then blows hot but the compressor is still on. I think my water pump may be leaking but that is probably a seperate issue.
Monday, October 19th, 2009 AT 11:12 AM

7 Replies

Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
Start engine.
Within 10 seconds of turning ignition on, press and hold A/C-heater control panel OFF switch button.
Hold OFF switch button for at least 5 seconds.
Select desired self-diagnosis step by rotating temperature dial clockwise or counterclockwise.
To advance to next self-diagnosis step, rotate dial clockwise.
To return to previous self-diagnosis step, rotate dial counterclockwise.
To access AUXILIARY MECHANISM: TEMPERATURE SETTING TRIMMER, select SELF-DIAGNOSIS STEP 5 and press fan up arrow switch. Auxiliary mechanism tests temperature setting trimmer.

This guide can help

https://www.2carpros.com/articles/car-heater-not-working


https://www.2carpros.com/forum/automotive_pictures/99387_Graphic1_562.jpg

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Tuesday, October 20th, 2009 AT 10:18 PM
Tiny
SUGAHBUGAH4
  • MEMBER
  • 1 POST
  • 2000 NISSAN MAXIMA
  • 2WD
  • AUTOMATIC
Heater only blows cold air at all times.
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Monday, November 11th, 2019 AT 5:26 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check coolant level first #1 cause of no heat. Then check to make sure both hoses going into heater are hot. Then check ducts and whether temp cable hasn't broken see pic if electrically operated make sure it's getting power to motor.
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Monday, November 11th, 2019 AT 5:26 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
  • 1999 NISSAN MAXIMA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 103,000 MILES
1999 Nissan Maxima mileage: 103,000. My daughter has a 1999 Maxima. The heater stops working when the RPM slows down. As long as she is running around 65 miles per hour, it works. If she slows down or has to stop, it stops. Any idea what this might be. She has a small baby and needs the heater working badly. We have asked everyone, nobody seems to have a clue. My husband thinks it may be the vacuum.
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Monday, November 11th, 2019 AT 5:26 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
The heater core in your daughter’s car is partially plugged or restricted nearly stopping the flow of coolant through it. Flushing it out or replacing it should correct her problem.
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Monday, November 11th, 2019 AT 5:26 PM (Merged)
Tiny
G0046H
  • MEMBER
  • 1 POST
  • 1999 NISSAN MAXIMA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 164,000 MILES
No matter what setting the controller is set on, (ac or heat), when the dial for increasing the speed of the fan on the heat or air, which goes from 1-5, is turned, nothing happens. Is this a fan switch or relay? Or is it the fan motor itself? Or could it be the controller? Fuses have already been elliminated.
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Monday, November 11th, 2019 AT 5:26 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi g0046h,

If fan motor does not work at maximum speed with fuses good, the most likely cause would be the blower fan motor.

Give the blower motor housing some banging and check if it starts working.

Test the blower motor connectors for battery voltage and use external power source to test if it works.
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Monday, November 11th, 2019 AT 5:26 PM (Merged)

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