Replaced display assembly and now the new display has no backlight

I just recently purchased a display assembly for my Macbook Pro 15 inch. I swapped it in and when I power it on, I get no backlight. I can see that the display is on and working but it has no backlight. I went ahead and put the old display back in and it worked, backlight and all. I’m not sure what’s going on. I did notice the LVDS cables had different part numbers. The old display assembly LVDS cable has part number GCQ1 and the new one has FW3F. I googled both of these and FW3F comes up with 13 inch assemblies while GCQ1 comes up with 15 inch ones. Wondering if that part is causing the issue or if it doesn’t matter? The FW3F seemed a bit short and it was a pain in the ass to get to fit in. Thanks