So my 2004 Mazda RX-8's air conditioning was all wacky during the summer, and now the heater won't put out anything but cold air, unless I play with the temperature **** a lot, then it will finally kick over to heat. My check engine light came on a couple weeks ago, so had my dad plug in his tester to it and it read,

P0037 bank 1 sen 2 heater circuit low

This makes sense when I saw it say heat since my heater hasn't been working, but I don't know exactly which one it is! Would this cause the heat issue? How do I and how much would it be to replace this? Will it hurt anything if I wait to replace it??

Please help!!
Thank you,
Sammie

 

Sounds like your climate control has some bad connections - causing your heat & AC issues. Search the forum for other heater control issues, may be a common issue.

The bank 1 sen 2 heater is an O2 sensor - the expensive ones have built in heaters to get them up to temp faster, resulting in better performance & emissions. So plan on at least $150 for the sensor + install - though the install should be pretty quick, maybe an hour.