I know the relay for the rear window defroster is behind the instrument cluster, but where is it exactly?

Pictures would be nice.

this is for the 77. the pictures i have for component locations are just terrible.

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

Left side. Its a 1" silver rectangle shape.

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84 300D, 82 Volvo 244Gl Diesel

thats for the later w123s. I have the first year of w123 and location of some items have changed such as the glow plug relay etc.

I tested the system today and I heard the relay working when I hit the switch. The fuse was good, power is getting to the switch and the circuitry to the window is good but it seems that there is an interuption in the window since I am getting infinite ohms across the 2 leads for the wire in the window.

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

I have a similar situation on my Rear Window with the exception that I had to re-solder my 2 leads back onto the window. After that I get it to conduct from the leads to the wide strips but cannot get it to conduct through the grids.
When I look at the grids (mine are on the inside exterior of the glass) there is no marks scratching through the grids and they look like they should work.
What I did notice is that instead of being copper colored or a color similar to other grids I have see the grid lines appear the (dark slate green) color of corroded copper as viewed from the inside. The grid lines also feel rough like they are corodded.
When I look at the grids from the outside to the inside the grid color is reddish copper colored. Except that when I look real close I can see many tiny dark slate green spots that go across the grid.
I believe that the slate green spots that I can see from the out side of the window are corroded spots that are creating broken/open circuits on each grid line.
I have not figured out what to do about this yet.
Permatex sells little viles of copper liquid to repair breaks in the grid but it was not ment to create a complet grid line and it is also $8-9 a vile and you would be lucky if there is enough in 1 vile to make 1 long grid line.

If what I say is true I would be interested in some ideas on repairing the grid.

Also, I tried hooking up the 2 leads directly to a battery with jumper wires to see if the grid would heat up; it did not work.

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84 300D, 82 Volvo 244Gl Diesel