There're VOLVO FL Truck Service Manual & Electric Wiring Diagram PDF above the page.
Volvo FL6 - truck chassis with a 4 × 2 wheel arrangement with a gross weight of 7.5 to 18 tons, which are designed to perform operations in various sectors of the national economy (but is most often found in the performance of a cargo van).
The first incarnation of the truck was born in 1985, at the same time its mass production was launched, and the most popular were the modifications FL 611/612/614/618 (where the first figure indicated the displacement of the engine, and the remaining two - the maximum mass in tons) .
In 2000, this line was modernized - as a result of which the “FL6” received: an updated exterior, a refined interior, modified engines (meeting Euro-3 environmental requirements) and an exhaust system.