No heat?

2000 NISSAN MAXIMA
160,000 MILES • 6 CYL • FWD • AUTOMATIC
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NEILB57
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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.
Oct 19, 2009 at 11:12 AM
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BMRFIXIT
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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

Oct 20, 2009 at 10:18 PM
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SUGAHBUGAH4
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Heater only blows cold air at all times.
Nov 11, 2019 at 5:26 PM (Merged)
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HMAC300
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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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Nov 11, 2019 at 5:26 PM (Merged)
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2CP-ARCHIVES
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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.
Nov 11, 2019 at 5:26 PM (Merged)
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2CP-ARCHIVES
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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.
Nov 11, 2019 at 5:26 PM (Merged)
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G0046H
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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.
Nov 11, 2019 at 5:26 PM (Merged)
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KHLOW2008
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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.
Nov 11, 2019 at 5:26 PM (Merged)