Really depends on year, engine, and what you're using it for. For a freight hauler running just a five axle unit, if you were to get a brand new one with the ISX, the engines of 450 horsepower or less for 2014 have their power band from 1250 to 1350 RPMs, so you might want to consider something like 3.36 rears with a .73 or .74 overdrive transmission, or possibly 2.93 or 2.85 rears with a .86 or .87 overdrive transmission. Then, there's always the I-Shift option, which is available only with a Volvo engine and comes with either a .9 overdrive ratio or a 1:1 direct drive ratio... If it were me, I'd probably go with the .9 and 2.64s, and just not use the big hole unless I was empty or loaded really light. But you should really talk to a Volvo rep about how to spec your truck... I wouldn't be the be-all, end-all source for that info... Volvo trucks aren't made for the lines of work I've been in.. they're aimed at freight haulers.
If you have the double bunk sleeper, it should come up to about 12'6".
You'd have to contact Volvo customer service for this. IIRC, there were a couple different options for the 730 and 780.
Any Volvo dealership, halfway decent truck stop, or - if a simple 12v cooler is sufficient (it was for me when I drove OTR), then you can find one easily enough at Wal Mart, Target, Best Buy, etc.
there are two old style fuses in line behind the fridge you must pull the fridge out of the cabinet to check them
Please go to this URL. I think 780 has the same relays and locations:
http://www.davebarton.com/pdf/relay_87_700.pdf
Igor.
Curb weight for a 780 is typically between 18,000 - 19,000 lbs.
Somewhere in the vicinity of 17,000 - 18,000 lbs.
To give an accurate answer, you have to give us an idea of how the truck is configured.. a 780 with standard 12k steer and 40k drive axles is going to differ greatly in weight than a heavy haul truck with, say, a 20k steer and 50k drive axles. The motor is going to affect weight, as well. The lightest motor will be the Volvo VE D 12, and the heaviest will be the Volvo VE D 16. In between those motors, there were several other motors available in various years - 12.7 litre 60 Series Detroit, Cummins M11, N14, and ISX, Caterpillar 3306, 3406, C12, C13, C15, and possibly the C16, etc...
It is the Volvo fuel injection relay . It provides the ground path for the fuel injectors.
According to info I found, Volvo 1323592-1 is used as a cooling fan relay and as a noise suppression relay.
20,000 pounds give or take some depending on fuel
You'd be in the 18,000 lb. range.
Assuming you're referring to a Volvo VNL 780 truck, with the double bunk sleeper, 12'6".