Now I know the $500 I paid to get mine installed was money well spent
Good on you for the DIY job though.
I will do DIY for some things but you do have to weigh up the amount of work involved & the skill level required & of course the tools you have.
I just put new LED's & rewired the boat trailer, not a hard job really but I almost had to go to an auto elec because I couldn't get the taillights on the trailer to work.
After getting the MM out & testing it all round the fault was actually in the cars wiring to the 7pin plug & not the soldering & rewiring I did on the trailer.
These things can be bloody testing at times
YouTube is your friend with these things & im sure you did a fair bit of it before your attempt?
if you didn't I sure would have!