Please Help 2004 TL with Nav
I have no power to my climate control system nor my heated seat. Fuses have been checked and the system is simply dead. Don't know if these 2 system share some type of relay (which I hope and pray is the case) or if the expensive motherboard part Ive been reading about. Everything worked fine the previous summer. I went this past summer with no a/c, no rear def. Its getting cold and time to bite the dealer bullet. Can someone please shed some light. I've read post dealing with these 2 issues separately but never combined.

 

Here is the fuses they share:
Under hood
22 (120A) and 23 (50A) both unlikely to be the source of your problem

Under dash
30 (7.5A) most likely to be the source of your problem


The seat heater system is very simply and is not composed of many components. If it's a compound problem, then fuse 30 is where it's at. Fuse 30 is for AC compressor clutch relay, climate control unit, power mirror actuators, and other HVAC related stuff. Check this one carefully even if it looks good it's worth trying to switch for another.

They also share a ground somewhere (G506) but this also the ground for audio amp, passenger lock switch, glove box light, right front side marker light and others. I imagine you would have noticed that.

 

30 amp fuses replaced, problem remains will check for proper ground.

 

I mentioned no 30 amp fuse. I mentioned fuse 30 under dash, which is a 7.5 amp fuse.

Something else to make sure is that the fuse box isn't defective/wires are loose behind it. It's one of these things you don't think about as it's not obvious like a blown fuse.