1990LS400

My understanding is that the manufacturer's warranty has always been the same on Lexus vehicles:  Basic warranty is 50,000 miles or 4 years, whichever comes first; drivetrain warrant is 70,000 miles or 6 years, whichever comes first.

My opinion is that automotive extended service warranties are rarely cost effective.  I retired from an insurance company that sold them and where employees could buy them at cost.  Few did unless they were buying a make or model with known issues -- mainly Chrysler products.

Service warranties are major money makers for automobile dealers and the insurance companies that underwrite them.  Yes, some buyers of service warranties come out ahead but that is quite rare.  If you "stretched" to buy your car, are financing its purchase, are sure that you are going to keep it at least as long as the term of an extended warranty, and cannot afford a "surprise" multi-thousand dollar repair then maybe an extended warranty is for you. 

For probably at least 20 years, a vehicle's turn signals and brake light circuits have been used only to "trigger" trailer lights.  The actual power for trailer lights comes from a much more robust source.

For example, the aftermarket trailer light harness on my LS400 takes its power directly from the engine compartment fuse box.  The little "magic box" that is the center of the aftermarket system routes current from the engine compartment fuse box to the trailer tail lights, stop lights and turn signals when it receives "signals" from the car's tail lights, stop lights and turn signals.  Your OEM system works pretty much like my aftermarket system but it is probably better engineered.

I hope your total trailer weight, including cargo, is a LOT less than 3,500 pounds or that you understand the implications of towing the maximum allowable weight. 

And exactly how is all this Lexus-related?

Huh?  The stated purpose of this "Club Lounge" is "Talk about other topics here not related to Lexus."

You have "ventilated seats" instead of cooled seats:  http://www.lexus.com...ront_seats.html

The seat ventilation system takes ambient air from the interior and circulates it though the seat leather perforations.  Instead of setting the HVAC on "auto" or to blow air only through the dash vents, try a manual setting to blow the air through the upper & lower vents so that cooler air gets nearer to the ventilated seat air intakes.