Hi, so when I bought my 2002 Civic LX the defrost grid worked but just barely; just a few lines worked. I tried to fix the contact but broke one off and decided to have the rear glass replaced. The defrost didn't work at all after that. The glass shop tested the grid which was fine. I replaced the defrost module in the trunk to no avail. The fuse is fine and the power mirrors work. The light on the button comes on. The relay wouldn't audibly click when the button was pressed so I replaced it but it still doesn't click. So could the button need replacing? The air circulation and A/C buttons next to the defrost button work. I'm not well-versed in electrical so don't really know how to test grounds and whatnot. Any help is much appreciated because driving around with no defrost in the winter, especially after shelling out $200 for new rear glass, is kind of a bummer. Thanks.

 

If just a few defrost lines worked then I would suspect you had some broken defrost lines that needed to be repaired.

There are 2 fuses to check for the rear window defogger. The #14 (7.5A) fuse in the Under-Dash Fuse/Relay Box and the #11 (40A) fuse in the Under-Hood Fuse/Relay Box.

 

I took a look; the fuse is intact and actually I had replaced it last winter.

 

I finally got around to replacing the switch which didn't help. So I've replaced both fuses, the relay (which does NOT audibly click), the switch, the glass, and the defrost/antenna module. Any ideas would be much appreciated.

 

Short in the circuit wiring? Ugh.