Ok i have been having a wierd and inconvenient issue happening the past couple of days. When i wake up in the morning driving to work or any time the car is cold and the heat is on auto i am getting nothing coming out of the vents even when the car is fully heated. Normally the fan kicks in slowly as the car warms up but now the only way to get it to work is to turn the heat off then back on once the car is fully heated.......right now it is just inconvenient but im afraid the heat is going to die on me during the winter and i will be freezing my *** off.

Anyone know what could be causing this? its an 07 g35 coupe

 

Try manually controlling it. Set it all the way up to 90 with the fan setting at 3 or 4. Does the issue go away once you start driving?

 

No even if i set the fan all the way up and temp to 90 the fan doesnt run. but if i press the off button and then turn it back on it will work fine. i dont understand it. but if it is on auto when i start the car it nothing happens even if the car fully heats up. but turning the heat off and back on always makes it work

 

Maybe you have an electrical issue. Because if its heating after the reset, then your issue isnt mechanical. The problem has got be with the fan electronics. Do you have an extended.warranty?

 

Also, does the fan run if the temp is at 60?

 

Check the blower motor or connection to the blower

 

You're sure you can fix it consistently by turning system off and back on? I had a similar issue, but not as consistent which is why I ask. My fix was a $35 blower relay which was not mentioned anywhere in the FSM troubleshooting and also not discussed anywhere on driver.

I'm trying to reason through what would be broke if turning the system off and then back on after reaching temp fixes it consistently. What if you shut the car off after the fan is working, does it immediately work upon restarting? Could be logic related which would be the control board for around $300 and not too difficult to replace. Just a guess.

 

^+1 I was thinking maybe a relay. Try seeking that route out first since its the most inexpensive route.

 

Here's my thread on the relay replacement. I did a DIY with pics and the part number is included:
https://g35driver.com/forums/general...ermittent.html

It is cheap so you could certainly take a stab at it, or continue troubleshooting. Someone here may eventually chime in with the same symptoms.

 

wow, spammers these days.....

 

IDK it seems like it has been getting worse today i had to switch the air on and off a few times after the car was fully heated to get it to work. this issue does not happen on warm days..... i really dont know whats going on it seems to work fine on a warmer day when it is probably trying to cool the car off

 

Does it ever turn on by itself after you've been driving for awhile? Test that without playing with buttons.

Your issue is starting to line up with the relay issue I fixed in mine. When the relay was warm enough it worked fine in delivering current to the blower. After driving for awhile, I'd usually get enough heat passing in from the engine bay to get the relay working. Warm days, always worked fine right away. Super cold days it would hardly ever work.

Take a look at my old thread linked a few posts above. Another test would be to blow drier the fuse box area (from a distance, don't go crazy just get some modest heat in there) to see if it the blower turns on after heating that relay up. I'd say more, but I did enough talking (to myself mostly ) in my thread.

 

revisiting this thread because it is getting cold and heat in my G is hard to come by these days, Sioux thank you for your help i think im going to try the relay. any suggestions before i start digging through the thread and ordering a relay? any help would be greatly appreciated


Also yes now that it is colder the heat never works. its really hard to get working and seems to only want to work when the car has been warm for a long time. but on a day with around 50 degrees or more everything seems to work fine! so frustrating and i work so much now its going to be hard to come by some spare time to work on this....i sure hope the weather is nice this weekend.

 

Ok so here are the symptoms as of now. This morning was foughly 34 degrees when i left to drive to work. the car fully heated up but no heat. i tried switching to defroster at 60 degrees and defroster at 90 degrees and regular heat at 60 degrees and 90 degrees ac on and ac off with no luck. Sometimes i have turned the engine off at a stop light and been able to get the heat to work but i havent been so lucky lately....Does this sound like a relay??? Thanks for all your help guys

 

25230-79942<-------this is the part number that i should order? where would you recommend ordering from?