button and wiring shall not admit spray nor allow water to accumulate in the wire way. The horn must be
capable of being heard over the engine noise during maximum DBP operation.
3.6 Winterization system. When specified (see 6.2), the vehicle shall be equipped with a winterization
system to permit storage and operation in ambient temperatures as low as -40° F. All heaters furnished
shall operate on 110 volt alternating current (AC) and shall be wired through a junction block to a single
three pronged (male) weatherproof slave receptacle for receiving external power and grounding the
vehicle. A three w-ire connecting cable, 25 feet long and of adequate line capacity to supply power for all
heater units simultaneously, shall be furnished. The connecting cable shall include a matching female
connector at the vehicle end and a standard weatherproof three pronged (two power, plus one ground) male
connector at the other end. Electrical apparatus shall conform to Federal Motor Carrier Safety Regulation
393.77 (c) (7). Electrical insulation of connecting cable shall withstand normal operating stresses in low
ambient air temperature without cracking or loss of dielectric capacity. All heater lead wires shall be
installed without interfering with vehicle component operation and without loose excess wire. Provisions
for storage of the cable shall be provided in the vehicle cab. A manual reset circuit breaker shall be
installed in the circuit inside the cab to afford overload protection. A red power or indicating light shall be
located on the dash panel and clearly marked. Heaters shall be furnished as follows:
Coolant heater, 1,500 watt minimum rating, shall be installed in the engine block or in the
lower coolant inlet hose. Engine thermostat, with an operating range of 170° F to 195° F,
shall be installed.
Immersion type engine oil heater, 300 watt minimum rating, with 170° F thermostat, shall
be installed in oil pan through any convenient opening.
Battery heater shall be provided, having a capacity adequate to maintain the battery
electrolyte at a temperature of not less than 10° F during vehicle exposure in ambient air
temperatures as low as -40° F, and shall embody a thermostat to limit the temperature of the
electrolyte to not more than 80° F.
A fuel warmer or preheater shall be provided to prevent clogging of the fuel filters due to
wax crystallization in the fuel. The fuel warmer shall use engine coolant to transfer
sufficient heat to the diesel fuel to heat it from an inlet temperature of -40°F to an outlet
temperature of +9°F, with a flow rate of not less than the maximum fuel demand of the
engine fuel system. A coolant shutoff valve shall be provided for the coolant inlet side of the
fuel warmer unit.
Aux iliary Equ ipment.
The hitch shall be supplied and mounted with the clevis center at a height of 14
inches above ground on both front and rear of the tractor. Pintle hooks shall have integral positive locking
device and secondary positive locking device both that will engage automatically. The rear mount may be
of the bolt mount design. The design load will be the rated load multiplied by a factor of three or a dynamic
load multiplied by a factor of two, whichever is greater. The pintles shall be in compliance with MS 51335-
2. A surge brake attachment point shall be located no more than 12 inches away horn the pintle and
fastened to a structural member other than the pintle. There shall be two safety chain attaching points, one
on each side of the pintle, equal distance apart, independent of pintle mounting, and capable of
withstanding shock loads up to 20,000 pounds.
Additional Pintle and Electrical Connection for Towing MHU-85 and MHU-173E Trailers.
When specified (see 6.2), the tractor shall comply with DL68E34230, or equivalent, except all
electrical/receptacle requirements of the DL shall be deleted and instead, the following drawing and
necessary hardware shall be included.
American Coleman, 540-140-009, Cable.
b. Berg, 740, Hook.