Rear defroster not working

Just did a test on defroster, I had a test light on rear defroster and had someone turn switch on and off at dash, the test light goes on and off each heat strip.

Hi,

Is it possible for you to check voltage on the grid? If you are getting power, it should work unless there is too much resistance from the repair and causing a drop in voltage.

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Let me know.

Joe

what should the voltage be on the grid?

Hi,

I have attached all the schematics I have related to the rear win defroster. As far as voltages, they will vary based on the temperature selected. For example, low will have lower voltage than high will.

So, here is my question. First, when you checked the voltage, was that at the window connector or a known ground? If at the supply connector, does it maintain power and not turn on and then off?

Let me know.

Joe

there is no adjustment for the rear window defroster, it's either off or on.

Does the power continue at the grid or does it cut off? If it continues, then either the grid is bad or there is no ground.

Joe

I had reinstalled the hot side tab. I touch tab with test light then touch all the grid lines and nothing. see picture.

That certainly looks like an issue. There is a TSB related to repairing the grid. Take a look through it and see if it helps.

________________________________
2007 GMC Truck Envoy 4WD L6-4.2L
A/C - Rear Window Defroster Tab Repair
Vehicle A/C - Rear Window Defroster Tab Repair
A/C - REAR WINDOW DEFROSTER TAB REPAIR
Bulletin No.: 03-08-48-006A

Date: November 08, 2006

INFORMATION

Subject:
Repair Information for Reconnection of Rear Window Defroster Contact or Tab

Models:
2000-2007 GM Light and Medium Duty Trucks
2003-2007 HUMMER H2
2006-2007 HUMMER H3
2005-2007 Saab 9-7X

with Electric Rear Window Defroster (RPO C49)

Supercede:

This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 03-08-48-006 (Section 08 - Body and Accessories).

Repair Suggestion

Electrically conductive epoxy repair kits have been successful in reattaching the electric defroster tab to the rear glass as an alternative to rear window replacement. Repair kits such as Kent Automotive P/N 57827-C and LOCTITE(TM) product # 21351, or equivalent, are commercially available. By following the manufacturer's recommended repair procedure specified on the kit and properly preparing the bonding surface, an effective repair may be achieved.

In addition to the strength of the bond, it is vital to strive for the best possible appearance. While it is unlikely that customers may refer to the appearance of the rear window defroster and its components as a positive styling feature of the vehicle interior, it is easy to elicit the opposite reaction due to a poor cosmetic application. If the tab (contact) is located in such a location or manner that an effective and attractive bond cannot be produced, window replacement is required and preferred.


pic1


Parts Information

Warranty Information (excluding Saab U.S. Models)


pic 2

_________________________

Is that the type of product you use for the repair?

Joe

Looks like I reinstalled the tab wrong, it's not making a connection. Is there away to remove the tab without breaking the glass? I installed the tab with that defroster epoxy.

Okay, the only thing I can tell you is try to carefully wiggle it to see if it will come out for you. You can contact the epoxy manufacturer and see what recommendations they have.

Let me know if you get it.

Joe

I applied a little heat with a heat gun and it came right off, I looked at bottom of tab looks like it was hanging on. thanks for the help.

Good idea!!! Were you able to get it working now?

Joe