One of my reverse lights was used for a fog light conversion.
Now that I've changed from hawk rear lights to blob I have a bulb in the reverse lense that does nothing. The other side reverse works great but I assume come MOT time it will fail as the bulb doesn't work.
can I take power from the passenger side reverse that works and splice the drivers side into it?

I don't really fancy making the now fog light a reverse light and then doing a new wire for the fog...

 

Reverse lights are not a legal requirement so it won’t fail a mot on it.

 

I heard they are now. Besides 2 super bright lights will help me see when reversing 🙂

 

Yes, you can just splice it in.
I'd be inclined to splice into the loom close to where it splits, then rewrap.
Neat electrics.