Why Does My Trailer Fuse Keep Blowing On My 2019 Toyota Tundra?

Question

Question:

Using the 7 way tester on 2019 Tundra, the 12V light would not light up all other lights lit up successfully. Identified that the 40 amp SUB BATT fuse was blown. Once this fuse was replaced, the 12V lit up. Any idea as to what would cause this particular fuse to blow or where to even start looking?

asked by: Dan

1

Helpful Expert Reply:

One of the most common reasons that your fuse may have blown is likely due a short circuit that is overloading your circuit.

More commonly this is caused by a dirty or corroded trailer connector on your vehicle. I recommend start by checking for corrosion and rust, and if there is clean the connector and check to see if the issue persists.

If your connector is fine, then I recommend checking your trailer wiring as your SUB BATT fuse is your trailer towing fuse. You'll want to check for pinches or frays, and replace as needed if need be.

Additionally, you can use a circuit tester # PTW2993 to narrow down troubleshooting when checking for problematic wires.

I have also included a FAQ for you to check out as well.

expert reply by: Bryce D

1

Answer 1

The auxiliary 12-volt wire that runs from the 7-way connection to 7-way trailer plug will supply 12-volt power from the vehicle to the trailer. The 12 -volt power will allow interior or exterior lights to run that are not wired in to the…

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Answer 2

To check the pins on the vehicle side 7-Way, you can use a circuit tester or the volt meter. The circuit tester will show you if a signal is coming through on the pin you are testing while the volt meter will tell you that and how much voltage is…

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Answer 3

In order to determine the torque rating for the lug nuts on your trailer you will need to know check out the chart I attached that shows all of the torque specs for all the trailer lugs available based on stud size, wheel material and wheel size.

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Answer 4

To correctly measure a leaf spring, you'll want to jack the trailer up on jack stands so the axle is hanging freely, then measure directly across from the center of one spring eye to the other, as shown in the provided diagram. The height of the…

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Answer 5

To find the load capacity for your axle you should look on the trailer VIN plate or sticker that lists the VIN number. The weight rating of the axle should be listed on that same plate or sticker. Also, the axle could have a tag or plate on it that…

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Answer 6

For a single axle trailer, you want the shackle strap to be able to move so that you have the spring deflection needed for your suspension. Angled like the photo or even almost vertical is fine you just don't want the shackle strap to bind and…

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Answer 7

I contacted MORryde and this does happen from time to time as the weight of the trailer can spread out the axles due to downward pressure on the springs/suspension. Odds are the 35" wheel base #MR27ZR will be the correct one for you, but they…

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Answer 8

Thank you for providing the specs for the suspension components that you already have. Correct hanger spacing really depends on the components being used such as springs, hangers and equalizers. Most of the hanger spacing dimensions that we have are…

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Answer 9

Yes, going from a 4 leaf to a 6 leaf spring would add slightly to your ride height. For example, if the current 4 leaf spring has 3/8" thick leaves, and you go to a 6 leaf spring with 3/8" thick leaves, you would be adding 3/4" of…

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Answer 10

Well shackle length is mainly based on the height difference between the front and rear hangers. The rear hanger normally doesn't hang as low as the front so that the shackle can offset the difference and add the ability to move. What is the…

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Answer 11

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

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Answer 12

Hey Patrick, so for your leaf spring upgrade I am going to need to know a couple of things before I can get you over to the right part. Specifically, the length from eye to eye, the spring width, leaf thickness, and the number of leaves. From here I…

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Why Does My Trailer Fuse Keep Blowing On My 2019 Toyota Tundra?

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