Tarp Motor — How to Tell When It’s Time for a Replacement

A sluggish tarp, a motor that grinds, or a switch that only works in one direction can shut a truck down in seconds. As a family-owned distributor, American Tarping keeps fleets rolling by stocking dependable tarp motors from Aero Industries, Buyers Products, Donovan, US Tarp, Mountain Tarp, Pioneer Coverall, Roll-Rite, Sioux City Tarp, and other trusted brands. The guide below walks you through a quick, 12-volt bench test you can perform in the yard or shop to decide whether your tarp motor is healthy, borderline, or ready for retirement.

(Note: These instructions are for diagnostic reference only. Always follow OEM procedures and use a qualified technician when in doubt.)

What You’ll Need

• A fully charged 12-volt battery (use two in series for 24-volt motors)

• Jumper leads or 6-gauge cables with solid clamps or ring terminals

• A clamp-style ammeter (optional, for amp-draw checks)

• The tarp motor you want to test
  
  

Step-By-Step Motor Check

1. Isolate the Motor
   Disconnect the truck wiring, remove the motor cover, and expose the two power posts. Eliminating the vehicle harness rules out broken wires or a bad switch.
   
   

2. Secure Your Leads
   Crimp ring terminals or lock your clamps onto the motor posts so you get a clean connection. Poor contact can mimic a weak motor.
   
   

3. Apply Power
   Touch one jumper to battery positive and the other to negative. The motor should spin smoothly and reach speed in less than a second.
   
   

• No movement? The motor is likely defective.
  
  

• Spins, but weak or starts then stalls? Internal wear or water ingress is probable.
  
  

4. Reverse Polarity
   Swap the leads on the battery. A healthy bi-directional motor will instantly reverse. If it turns only one way, the internal brake or commutator is failing—or the switch on the truck is stuck, which we’ve already ruled out by bench testing.
   
   

5. Optional Amp-Draw Test
   Clamp the ammeter over the positive lead while the motor free-spins. Most 12-volt tarp motors draw 10–15 amps unloaded. If you see 25 amps or more, resistance inside the gearbox or armature is climbing—time for a new unit.
   
   

6. Inspect Grounding on the Vehicle
   When reinstalling, run the ground cable directly to battery negative, not to the chassis. Frame grounds corrode and create voltage drop that shortens motor life.
   
   

Common Field Symptoms & What They Mean

• Runs only in one direction: Swap the two motor wires. If direction changes, the rotary switch is bad. If not, the motor has failed.

• Tarp rolls back when the switch is released: The motor brake is worn; replacement is the cure.

• Grinding or squealing: Remove the plastic cover. If noise remains, gears are deteriorating—replace before complete failure.

• No action, switch light on: Power reaches the switch but not the motor. Check for sliced, pinched, or corroded 6-gauge cable; then test the motor with the procedure above.
  
  

Ready to Replace? American Tarping Has Your Motor

• Buyers Products High-Torque Motor #5543895 – 90:1 gearbox, bronze gears, chrome weather cover, three-year warranty; replaces Roll-Rite 1030, Donovan 61G, Shur-Co 1703823, and more.
  
  

• Donovan Durabuilt™ Universal Motors – 600 W and 900 W options, five-bolt plate fits nearly every tarp brand, fully sealed casings.
  
  

• US Tarp Bulletproof Slim #13655 – 50:1 ratio, slim profile for tight cab shields, three-year warranty.
  
  

If you need a different brand, power rating, or shaft length, we offer dozens of models—and if we don’t have it listed online yet, we’ll source it fast. 

Why Fleets Choose American Tarping

1. Lower Prices – We’re a distributor, not a manufacturer, so you don’t pay factory overhead.

2. Expert Support – Real technicians answer the phone and walk you through diagnostics.

3. Fast Shipping – Most motors leave our dock the same or next business day.

4. Family-Owned Values – We treat your downtime like our own—because that’s how we’d want to be treated.
   
   

A tarp motor failure doesn’t have to sideline your operation. Use this quick-test guide to pinpoint the problem, then rely on American Tarping for the right replacement—so your loads stay covered, your drivers stay safe, and your trucks stay on schedule. Call (786) 708-6662 or email support@americantarping.com Today!