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30,000 BTU 12 Volt Auxiliary Heater

Part Number: 55-390

Price: $268.50

In Stock, Ready to Ship!

High Output 30,000 BTU 12 Volt Auxiliary Heater with mounting brackets, switch, and hose connectors. This unit uses a single motor with dual blower wheels for superior output.

This versatile heater may be mounted either horizontally or vertically. Typical locations include floor, wall or under dash. A simple connection to the heater hoses is made by marking the inlet and outlet tube locations and cutting a hole through the vehicle’s floor or firewall. Grommets are included to protect the heaters hoses when going through the floor or wall. Mounting brackets are provided and the assembly has screws located on both sides for a quick assembly in any direction.


  • Full front opening for blowing heat
  • Dual blower wheels
  • Quiet operation
  • 3-Speed Switch
  • Hot water forced air heat
  • High efficient aluminum heater core
  • Powder coated steel case

Hardware Kit Includes:

(2) Mounting Brackets
(2) Y Splicers
(2) Rubber Grommets
(8) Hose Clamps
(4) Screws
(1) 15 AMP Fuse
(1) 3 Speed Switch
(1) Control Knob

Routing Heater Hoses and Connections
Route the heater hose to the engine compartment. It is recommended the heater hose follow the inside of the frame rails for protection from road debris when they are needed to run under the floor. Wire ties or clamps may be used to secure the hose to the frame. Please note that all hoses must clear all driveline or moving parts and must be securely fastened to the frame to avoid potential damage to the hose and cooling system. In the engine compartment, locate where the existing heater hoses pass through the fire wall. On the engine side of the fire wall, cut and insert the Y splicers in the existing heater hoses as close to the firewall as possible. Secure the 'Y' splicer connections with hose clamps (these components are provided in kit), then install the new heater hose to the auxiliary heater. Avoid any sharp bends which may kink the hose and restrict proper flow.

Wiring the Switch
Mount the switch in a convenient location. Route power supply wire from fuse block to 3 speed switch (to C), including inline 15 AMP fuse. Clip plug, then connect the red (to M), orange (to H) and yellow (to L) wires from the heater to the switch. Ground the black wire to the chassis of the vehicle.

This unit has a one year warranty from the date of installation.

Estimated Shipping Dimensions: 17" x 11" x 7"

Weight: 12.51 lbs


Mill Supply has been the #1 supplier of step van parts for over 30 years. If you have a Workhorse, Utilimaster, Grumman, Morgan Olson, Supreme, International or other type of walk-in van you have landed on the right page. You will not find a more complete listing of parts for stepvans anywhere! With research and development on-the-go, new products are constantly being added to keep up with the growing industry. You can count on great customer service, fast shipping, and discount prices when you shop with us. It doesn't matter if you use your truck on-the-job, for deliveries, or run a food truck, you can count on Mill Supply to keep your vehicle in top shape. We distrubute parts for Todco, Whiting, Velvac, Northern and Kason. If you have any questions don't hesitate to either contact us via email or give us a call at 800-888-5072 between 8:00 a.m. - 5:00 p.m. E.S.T. and one of our experienced representatives will be happy to help you.



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