If you have the 4sp auto 42RLE then the only switch I can find relevant is the Transmission Range Switch.[https://html2-f.scribdassets.com/8a5iqmyd8gf4rp3/images/16-9c765ccf06.jpg|43RLE] Bottom left picture switch number 3. Again called a TRS. The other two are input and output switches.
If however it is the 3 speed auto either the 30/32RH unit then it is a 3 pin neutral/safety switch. [https://html2-f.scribdassets.com/4jht29xegwf4rnv/images/38-e55b6fcf20.jpg|location]
That might look something like this, [https://www.morris4x4center.com/media/catalog/product/cache/1/image/800x800/9df78eab33525d08d6e5fb8d27136e95/5/6/56028181ab_1_4530.jpg|3 pin]
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Based on that location picture, I think we are looking at an upside down view of the tranny. As that looks a lot like the edge where the pan sits. So I'm going to say left hand side, lower.
If you have the 4sp auto 42RLE then the only switch I can find relevant is the Transmission Range Switch.[https://html2-f.scribdassets.com/8a5iqmyd8gf4rp3/images/16-9c765ccf06.jpg|43RLE] Bottom left picture switch number 3. Again called a TRS. The other two are input and output switches.
If however it is the 3 speed auto either the 30/32RH unit then it is a 3 pin neutral/safety switch. [https://html2-f.scribdassets.com/4jht29xegwf4rnv/images/38-e55b6fcf20.jpg|location]
That might look something like this, [https://www.morris4x4center.com/media/catalog/product/cache/1/image/800x800/9df78eab33525d08d6e5fb8d27136e95/5/6/56028181ab_1_4530.jpg|3 pin]