Rear Defrost Issues (1 Viewer)

[residualboulders]

New to me 80. Seems like the rear defrost is not working. Either that or it works very slowly. Fuse is good. Switch Lights up. I do have power to the connector on the drivers side or the rear window, none on the passenger. I assume drivers side is hot, passenger ground? Any idea what to check next?

 

[Runtble]

Common issue on these is that the connections (heating elements) will burn out over use. Mine does the same.

 

[shocktower]

Mine is crap too, and the rear windows are very expensive

 

[effjay80]

I had to gently reflow the solder where the connector attaches to the element in the glass as that connection was broken. You can check if the elements in the glass are getting voltage with a multimeter and small piece of aluminum foil across the glass over the embedded elements.

 

[b16]

I had to get one of those rear defroster stick on kits for the glass because nearly all the original elements were broken.

 

[SmokingRocks]

There are repair kits out there for the elements. Also endless youtube videos detailing how to test and repair them.

Also get your FSM at the link in my signature, it has the electrical wiring diagram (EWD) that shows this circuit.

 

[residualboulders]

Thanks for all the replies, looking at the window I don't see anywhere the elements are broken. I'll see if I can test them as @effjay80 has suggested.

 

[BTLSHP]

I am working from page BE-60 in the FSM on the rear defogger. I get zero defogging at this point. These are my mid-window voltages starting at the top:

1 - 6.7v
2 - 6.7v
3 - 6.7v
4 - 7.0v
5 - 6.2v
6 - 5.1v
7 - 6.0v
8 - 5.1v
9 - 6.5v
10 - 7.4v
11 - 6.0v
12 - 7.0v
13 - 7.0v
14 - 8.6v

Looking at the wires, it is hard to tell what I see; corrosion? There was a sticker removed from the lower left that might explain rows 12-14.

Separately, disconnected tab to tab resistance is 13.6 ohms. Voltage wire connector to wire connector disconnected 12.3v. When connected, the tab to tab voltage is 11.3v.

I guess I was assuming from these results, I would have partial performance at the top of the grid, say rows 1-8. I have seen nothing but will look on another day.

Any suggestions at this point? I am prepared to buy one of the paint kits, but I am not certain that is my only issue.

Thanks

 

[BTLSHP]

Separately, disconnected tab to tab resistance is 13.6 ohms. Voltage wire connector to wire connector disconnected 12.3v. When connected, the tab to tab voltage is 11.3v.

There was an obvious measure missing across the vertical conductors at the edge of the glass, it is 12.3v and when I rechecked the tab to tab it was 12.3v