2008 Snowplow-mounting guidelines

Sept. 1, 2007
Ford has made the most significant changes in the manufacturers' snowplow-mounting guidelines for the 2008 model year. The Smart Power Distribution Junction

Ford has made the most significant changes in the manufacturers' snowplow-mounting guidelines for the 2008 model year.

The Smart Power Distribution Junction Box (SPDJB) was incorporated in the 2008 model year and affects the F-250/350/450/550, as outlined in Bulletin Q-155-R1. Its job is to provide protection against excessive current loads, typical of a short circuit, by shutting down circuit function. The “low-beam” circuit (or “auto-lamps”, if so equipped) is protected by SPDJB-integrated circuit strategy that shuts down headlamp function when it detects excessive, predetermined, current levels (ie, larger than a 55-watt bulb load) or short-to-ground.

The SJB strategy may interpret the switching between Ford headlamps and aftermarket snowplow headlamps, and vice-versa, as a short-to-ground, causing the power feeding a headlamp circuit through the SJB to be turned off.

According to Q-155-R1, the following are examples of normal snowplow headlamp activity where this may occur:

  • Disconnecting the snowplow headlamp connector for a functional-test during installation. If wired for “automatic” operation, then the snowplow headlamp current is immediately diverted to the Ford headlamps. SPDJB interprets the immediate in-rush current to a cold Ford lamp as a short-to-ground.

  • If wired for “manual” operation, identified by a separate aftermarket headlamp switch, then any switching between the Ford and snowplow headlamps after one headlamp system has already been illuminated through the SJB will trigger a shut-down.

  • Normal daily snowplow hook-up if Ford headlamp is ON in “low-beam” (or “auto-lamps” active if so equipped).

The effect of an SPDJB shut-down event:

  • Full Ford headlamp function can be restored by turning the Ford headlamp switch off and back on again. However, a short-to-ground DTC code is flagged and will not clear until approximately 80 key-on ignition starts. The codes are B2A2F (right-front low-beam) and B2A31 (left-front low-beam). Also, the event is stored and after 200 events, a Ford dealer will be required to clear codes and return normal headlamp switch function. This repeats at 400 events, and at 600 events, the SJB will require replacement.

  • Open circuits will not have an affect on SJB diagnostics during normal operation.

Customers may have their Ford dealer reprogram the Smart Junction Box (SJB) with a new calibration using Technical Service Bulletin TSB 07-09-01. After reprogramming, no other operator intervention is required.

New vehicles from KTP with “Snowplow Prep Package Option” (Order Code 473), or “Snowplow/Camper Prep Option”, and with a build date of April 18, 2007, or later, already have this new calibration included.

Relay-driven functions such as the Ford high-beams or park-lamps are not monitored by SJB control strategy. Therefore, if required prior to applying the TSB, the snowplow can still be used because the SJB will not affect snowplow headlamp operations with the Ford headlamp switch in either the “OFF” position, or “ON” in parklamp position, or “ON” with high-beams activated.

For Dodge in the 2008 model year, while the gross architecture on the Ram 4500/5500 is similar — the distance between the rails is roughly the same — the design of the rails is “totally different,” according to Chris Borczon, chassis engineer for the commercial vehicle team.

“The 3500 and pickup truck have hydroform rails, and the 4500/5500 have welded C-section rails that form a box,” he said. “In addition, they are positioned slightly different — 11mm difference. The other big change is that there are much larger tow hooks with a unique attachment method.

“I've had discussions with snowplow manufacturers at previous NTEA (National Truck Equipment Association) meetings, and they are aware that the substantial attachment points that are designed for tow hooks are actually ideal attachments for snowplows as well. I've provided them with CAD data to design their plow attachments.”

Said David Donnelly, electrical engineer for the commercial vehicle team, “I think the mounting hardware the companies have created will work on this vehicle as well. Although the frame is larger, we've tried to keep it as common as possible so the snowplow installers don't have to go through a second iteration. For 2008, the circuitry is the same and the electrical interface is the same.”

General Motors announced no major changes for the '08 models.

The following list is for quick reference only. For a comprehensive list of the specific guidelines for each model, refer to the body builders book published by the truck manufacturer.

General Motors

GM recommends that when a snowplow is mounted on a vehicle, only one passenger should accompany the driver. More than one passenger may exceed front Gross Axle Weight Ratings.

Prior to installing a front-mounted snowplow, the following process should be followed and necessary information obtained:

  • Establish vehicle curb weight.

  • Establish chassis manufacturer's front and rear axle weight ratings.

  • Chevrolet and GMC truck dealers can provide availability, specifications, GVWR, and Front and Rear GAWR. For vehicles already built, this information can be found on the certification label installed on the driver's door/frame or provided on the cover of the Incomplete Vehicle Document.

The following information should be obtained and provided by the manufacturers of snowplows and salt spreaders:

  • Specifications, weights, and center of gravity data.

  • Vehicle installation guidelines and instructions.

  • Calculation of weight distribution for the front and rear axles.

The loaded vehicle with driver, passenger, aftermarket accessories, snowplows, spreader, and cargo must not exceed the GVWR, and Front and Rear GAWR.

In addition, the completed curb weight vehicle, with all installed aftermarket accessories, snowplow, and spreader, and with 400 lb distributed in the driver-passenger area of the vehicle, must have a center of gravity that is located within the trapezoid formed by the coordinates A, B, C, D, H1 and H2, plus it must be to the rear of vertical line E and forward of vertical line F as defined in the Allowable Center of Gravity charts. If the center of gravity does not fall within the specified trapezoid, ballast weight may be required to shift the center of gravity until it falls within the specified trapezoid.

The snowplow manufacturer and the installer of the aftermarket equipment should determine the amount of rear ballast required to ensure that the vehicle, with the attached snowplow and aftermarket equipment, complies with the Allowable Center of Gravity Trapezoid and the resulting front and rear weight distribution ratio as defined in the Allowable Center of Gravity Charts published in the GM manual.

The use of rear ballast weight may be required to prevent exceeding the GAWR of the front axle. The use of rear ballast weight may be required to ensure that the center of gravity location of the completed vehicle, with the attached snowplow and other installed equipment, complies with the Allowable Center of Gravity Trapezoid and the resulting front and rear weight distribution ratio, even though the actual front weight may be less than the GAWR of the front axle. In either case, the rear ballast weight should be securely attached in the cargo box or behind the rear axle of the vehicle in a manner that prevents it from moving during driving and stopping.

To help avoid personal injury, refer to Z-height setting procedure before adjusting torsion bars. If torsion bars are adjusted for aftermarket equipment, be sure to return them to specification when the equipment is removed. Otherwise, a front shock absorber may dislodge and damage a front brake line. This could result in an accident when minimum stopping distances are required.

Ford Trucks

Minimum recommended equipment for the F-150: regular cab 4×4, 144.5" wheelbase, 8' pickup box; or SuperCab 4×4, 163" wheelbase, 8' pickup box.

Snowplow prep package (option code 63A) includes FGAWR upgrade to 4300 lb (4300 lb spring rating).

Heavy Duty Payload package (option code 627) includes: 8200-lb GVWR; 4050-lb FGAWR (4050-lb spring rating); 4800-lb RGAWR (4900-lb spring rating); rear axle capacity upgrade to 5300 lb and 10.25" diameter ring gear 4.10 ratio, limited-slip not included but available; 17"×7.5" J 7-lug steel wheels; LT245/70Rx17D BSW all-season tires (5); 5.4L, 3-valve V8 engine, 4R75E automatic transmission; Super Engine Cooling (1.42" core thickness); auxiliary transmission air cooler, oil-to-water increased to 9-channel/18-plate; battery upgrade to 72 amp-hr/650 CCA; fuel tank (35.7-gallon capacity).

Snowplow weights (maximum recommended):

  • Regular Cab 695 lb (645 lb removable plow assembly plus 50 lb permanently attached hardware).

  • SuperCab 535 lb (485 lb removable plow assembly plus 50 lb permanently attached hardware).

These snowplow weight limits are based upon a vehicle built with maximum buildable Ford option content, driver plus one front seat passenger, 150 lb each, 800 lb of ballast weight rearward of the rear axle, and additional assumptions for commercially available snowplow assembly weights and mounting location.

The vehicle must not be operated when overloaded. A vehicle is overloaded when the weight of the completed vehicle with aftermarket equipment installed, plus driver, passengers, and cargo, exceeds either the FGAWR, RGAWR, or GVWR established by Ford Motor Co and displayed on the Safety Compliance Certification Label.

The addition of ballast weight placed rearward of the rear axle may be required to prevent exceeding FGAWR, and provide good vehicle braking and handling. The ballast should be attached securely to the vehicle with consideration for the normal driving dynamics of snowplowing and occupant safety in accidents.

For Ford completed vehicles of 10,000 GVWR or less, the weight of permanently attached aftermarket equipment must not exceed the Total Accessory Reserve Capacity displayed on the Safety Compliance Certification Label to maintain the compliance representation that came with the Ford-built vehicle. Exceeding TARC will require recertification. This applies only to the permanently attached equipment, such as the snowplow frame mounting hardware, and not to the removable portion of the snowplow blade assembly.

Front end wheel alignment (toe) and headlight aim may require re-adjustment after installation of snowplow equipment. Failure to reset front wheel alignment may cause premature uneven tire wear. If required, reset to chassis manufacturer's specifications found in the Ford Shop Manual.

Installation of any inductive load devices such as electric motors, or electric clutches for clutch pumps, must not be connected to Ford vehicle wiring or fuse panels. Power for such devices should be taken directly from the battery or starter motor relay power terminal. Control of these devices should be achieved via relays. No direct current path should exist between Ford vehicle wiring and the installed load that is not filtered by the battery. These recommendations are intended to eliminate or minimize any induced reverse voltage into the Ford circuitry.

Dodge Trucks

The loaded vehicle, including all aftermarket accessories, the snowplow system, passengers, and cargo, must not exceed the gross vehicle weight (GVW), front or rear gross axle weight (GAW) ratings specified on the Safety Compliance Certification label located in the driver's side door opening.

The empty truck with all permanently attached accessories and snowplow components must not exceed 62% of its total weight on the front axle to comply with FMVSS/CMVSR 105 Brake Certification. Permanently attached snowplow parts are those parts not easily removed when the blade is removed. The permanently attached parts are: subframe, hydraulic pump, hydraulic lift cylinder, lamps, wiring, snowplow controls, etc. If the front axle loading exceeds either 62% of the empty truck total weight, or the front GAWR, ballast compensating weight must be securely attached at the rear of the truck to bring front axle weight within weight specifications.

Notes for heavy-duty snowplows:

  • At any time, the maximum number of occupants in the truck must not exceed two.

  • Under any circumstances, vehicles should not exceed GVWR (Gross Vehicle Weight Rating), front or rear GAWRs (Gross Axle Weight Ratings).

  • Snowplow prep packages are not available with Sport (AAG) package.

  • Cargo capacity will be reduced by the addition of options.

  • Ballast should be securely attached inside the box at 9" from the rear tailgate for pickups.

  • The total weight of permanently attached hardware should not exceed 125 lb.

  • Max snowplow weight should not exceed values for models shown in this section.

About the Author

Rick Weber | Associate Editor

Rick Weber has been an associate editor for Trailer/Body Builders since February 2000. A national award-winning sportswriter, he covered the Miami Dolphins for the Fort Myers News-Press following service with publications in California and Australia. He is a graduate of Penn State University.