Thanks for the info but will be doing a lot of trailering this summer with two different trailers as well as a camper and don't want to risk overloading my truck lights. Decided to bite the bullet and consulted the top electrician at my Dodge dealer. His verdict: the trailer light relays are built into the TIPM on my 2005 Ram 2500 diesel, cannot be removed or replaced and the entire unit is "unflashable" meaning it can't be reset or updated. A new TIPM cost $377 in Denver plus an hour or so for labor to reprogram it. The good news, if there is any, is that the new modules have been updated to correct what is or was a very common problem in 2003-2006 Rams, namely the trailer tow left turn signal/brake relay output fries without blowing a fuse, necessitating replacement of the entire TIPM or, as weedahoe so rightly points out, a T-connect to the truck's taillights. The Dodge electrician points out, however, that even with diodes a T-connect could cause other problems, such as a "light out" warning on your dash or an overload in other circuits that would again fry the TIPM. I'm no expert, just passing along what I was told and since my Ram is the only wheels I got living where I do in the mountains, I have to be extra careful.