Tundra peeps, I can't believe this, but google is not coming up with anything.
My brother gave me a couple of these units when a shop he worked for closed down. Its made by Denso, is a factory Toyota part and is labeled as a "Toyota Towing Converter". It has various numbers on it:
And a harness with the numbers too eroded off.
Google doesn't pop anything up, but he said it was an add on for a towing package. Its a harness and electronics unit that doesn't have any controls on it. Picture is uploaded. WTF is this thing?