I have a 2008 suburban and rear defrost is not working, fuse is good, there is a wire on both sides of glass, with the switch on passenger side has power but drivers side doesn’t.
Any help appreciated
Thanks

 

With the switch on, One of the grid contacts provides power and the other provides ground.

If you have power on one, use a powered test light to check the other side for ground. If it’s good, there’s a problem with the defroster grid.

If not, there’s an open on the ground circuit. If you have a 1 piece lift gate (glass doesn’t open) the ground point is at the base of the right B pillar. If you have a 2 piece lift gate, the ground point is on the right D pillar.

In either case, the most likely problem (if the ground is open) is the section of the harness that passes from the lift gate to the body.

 

Thanks for your response Gumby22,
I have a 2 piece tailgate glass opens, where is the right D pillar? I assume it's what the right side of the tail gate sits against when closed?
FYI, I just glued the right side back on with the Permatex rear defogger kit. Is it possible I didn't get it positioned right?
Thanks for the help.

 

Yes - the D pillar is where the lift gate seats against. The most likely place for the ground point is near the bottom, under the trim.

FYI the pillars are labeled according to the position relative to the front, so the pillars the windshield is mounted in are the A pillars, the ones between the front and rear doors are the B pillars, and so on.

If you followed the directions included with the repair kit, it should be fine, but it’s possible it’s not making adequate contact.

You can verify the repair with an ohm meter - place one lead on the wire contact on the side facing the front and the other lead somewhere on the defroster grid - it should read 0.5 ohms or less if it’s making good contact.

 

Hey Gumby22, I ended up replacing rear glass because I couldn't get it to work, thought i was good but no still not working??? I did the ohm test as you said on the new glass and it comes out at 02.5 ohms, that was touching one lead connector and one of the grids, Right?. I looked at the ground behind the D pillar and it looked good and tight.
Any other ideas?
I appreciate the help.
Rob

 

Also I took a test light and i have power on the right side and as i go across touching the grid it dims till i get to the left side and doesn't light at all.

 

that is normal; as you go across the grid all available voltage is used up. if its still not working; how did you verify the grd side connector?

 

I think they are working now, this morning i had an inch of snow stuck to the back glass and had the defrost on but it wasn't melting ,I then took a thermometer to the grid and it was actually started heating up. Thanks for the help.