Low coolant, bad coils, perforated radiator hoses, blockage of the vents.. it's a bit difficult to pinpoint without knowing the conditions and circumstances under which it happens. For instance, if you're an OTR/Regional driver with something like Detroit Diesel's Optimum Idle system, and it fails to kick on when the motor cranks over, it may be the result of electronics failure.
An aerodynamic cab one, like a Freightliner Cascadia, International ProStar or Volvo VN680.
The heater isn't an extra unit, it is simply pulling heat from the engine and blowing it into the cab. If the engine is not hot the heat will seem like it is not working. If the heat is not working after the engine has warmed up, you may have a fan that doesn't work, or a clogged vent.
If it's a sleeper cab truck, the most you can do is slide the seat back. If it's a daycab, there really isn't much you can do.
With the cab fairing up top on the midroof, the aerodynamics should match, and there'll no MPG difference.
Ultra Magnus, a chief lieutenant of Optimus Prime in the Transformers series, can transform into many vehicles, including Freightliner Trucks' Car Carrier, the Kensworth Oil Tanker, the Freightliner Cab-over, the Cybertronian Truck, and the Nissan GT-R.
'Bobtail' does nothing to indicate the height. You'd have to be more specific, e.g., a truck with a 70" condo sleeper, or a day cab with a low roof, etc.
No way to know without knowing specific make and model, type of fire truck (tender, hook and ladder, etc), who manufactured the firefighting apparatus (Freightliner makes the chassis and cab - everything else was made by someone else), overall condition, etc.
You're talking about a truck classification exclusive to the US... of Class 8 truck manufacturers in the US, Peterbilt, Kenworth, and Freightliner still manufacture cabovers... just not for the US market, although Freightliner does appear to be reintroducing the Argosy to the Canadian and Mexican markets.
a loose wire or a broken switch inside the cab
Yes, it can.
Could be, Low on coolant, Plugged heater core, Faulty temp blend door actuator,
Antifreeze is used to heat the cab of your vehicle. When you turn on your heat in your cab, it opens up a valve that allows the hot antifreeze to flow from the radiator into the heater core. If there is a leak in the rubber tubes that flow into the heater core, or if the heatercore is damaged, you will smell the antifreeze in the cab of the vehicle. You may need new hoses to the heater core and/or a new heater core.