2003 Nissan Altima Rear Defrost Button Not Lighting / Not W

The owner's manual should indicate which fuse. That needs checked first. Next, you need to see if there is power to the switch itself. If there is, check the output of the switch for power. It's my gut feeling that the switch itself is the problem.

Check that and let me know what you find. You can check it with a simple test light. IF you have questions, let me know. Also, if you can't find the correct fuse, check for power to the switch. IF there is power, the fuse is good. If there is no power, then we need to check / find the fuse.

Joe

Okay, I did some homework. THis is a somewhat basic set up. First, power is supplied through fuse #12. It's a 10 amp fuse (under dash). From there, the power goes to the switch on the dash and then to a rear window defogger which is behind the left side of the dash. Something tells me that is what you are hearing. From there, it goes to a rear window defogger condencer near the base of the left C pillar and then finally to the defroster in the glass. A red wire powers the defroster at the glass, and then it goes straight to ground after exiting the defogger (black wire).

I need you to check two fuses, both #12 and fuse #8 which is also a 10 amp. The power comes from #12 through the switch and then through #8 which distributes power to the mirror defogers and rear window.

Since you hear the clicking, if any fuse is bad, my guess would be #8, but check both. Also, I uploaded the picture below. You won't be able to read it because of its size. I was hoping you could enlarge it to read it.

Let me know about the fuese. If they are good, we will need to start tracking down the wiring to see where power is lost.

let me know what you find.

Joe

That is a good question. If I recall, the power just went from one fuse to the switch, to the next fuse and then to the defroster. There has to be a break in that wiring or the defroster grid has been damaged.

I hate to say it, but some thing tells me the switch is bad. Are you able to check voltage in to the switch and then back out? I have seen switches that will provide power, but as soon as there is a load on it, they can't maintain the load. If you can check the power from the switch, check it with the key on and see what happens when you turn the defog on. I would like to know if the output maintains 12 volts.