My 11 year old and I replaced the Tongue Lift today. Nice and easy job especially since the only other job we've done is install combination bin locks...
We lifted the rv up on 4x4's, unscrewed the three bolts on the top side of the frame, and pulled out the manual lift. The we just inserted the new one, used the same bolts, and tightened it down.
The red fuse circular cable confused us, but we read that we had to cut it and then attach it to the end of the positive cable. It's odd that they just don't put it on the end of the cable. Also, there was no negative cable included as it expects to be connected to a frame that is connected to the negative side of the battery. It didn't work until we connected a wire to the battery.
We went to auto zone and bought some 10 gauge cable for the negative wire, crimping cable connectors, two loop crimping connectors to go on the battery, and two smaller loop crimping connectors to go on the lift as the negative cable.
We wired it up and it works!
I bought this powered lift
In the second picture, my son had the smart idea to use the small loop on an existing screw. I was going to drill a hole and set a screw... He saved us a bunch of time.