Brake Controller Recommendation for a Truck with Air Brakes and a Trailer with Electric Brakes

Question

Question:

I just purchased a 33 gvw truck with air brakes. I thought I could simply plug in to the 7 point connector to the back of truck and connect to the trailer. The trailer has all the dot safety and break away controls on it. I was told that the truck needs a converter from air to electric. Seems strange since I have electric for lights.

asked by: Mike L

0

Expert Reply:

The trailer brakes work on a separate circuit than the lights. You have a couple of options to control the electric brakes on the trailer.

One option is to use an air over electric brake control, # HA100400C. This unit connects to the air brakes on the truck and when the brakes are applied it sends an electric signal back to the trailer brakes.

The other option, and what I would do, is to use an electric brake controller like # 90885. For either of these controllers, the red wire attaches to the cold side of the brake switch or any dedicated brake light circuit, like the center high mount stop light (CHMSL). It must connect to a wire that only shows power when the brake is pressed and not also when the turn signals or running lights are on.

The black wire connects to the positive battery terminal on the vehicle via a 20 amp circuit breaker # PK54520 for 2 to 4 brakes or a 30 amp circuit breaker # PK54530 for 6 to 8 brakes.

The blue wire will connect to the back of the 7-Way in the 7:00 position. On # 90885, the white wire grounds to the negative battery terminal. I have included a link to the isntallation details for 90885.

expert reply by: Michael H

0

Scott

4/10/2024

Michael: I need to pull an electric brake equipped trailer with my semi power unit. As you suggested I am planning to install the #90885. I have a 7 conductor semi plug on the truck. Is there a converter available to adapt from the Semi 7 conductor plug to the RV 7 conductor, including the required circuit drop and circuit add for the electric brake circuit? Thanks, Scott

Reply

Answer 1

The Prodigy P3 part #90195 will work for you because your trailer has electric brakes. The P3 can install and work just fine on vehicles with air brakes. The only thing it needs from the vehicle is access to a circuit that only sees voltage when…

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Answer 2

On a 7 pin round which is the common connection on a semi trailer, the clearance/marker lights are at the 10 o clock position when you look at the trailer wiring connection. When looking at the connector on the back of the truck, that will put the…

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Answer 3

You can use the Pollack #PK11700 to install on your gooseneck trailer and create a 7 way plug capable of fitting on the 7 pole round plug that is on a semi tractor trailer truck. For the wiring you can use the Deka Jacketed 7 Wire #DW04914-1 which…

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Answer 4

The wiring on a semi is not normally the same as a standard RV or Gooseneck trailer. You will need to use a couple different harnesses to get what you are looking for. I recommend the ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat…

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Answer 5

You certainly can! Installing a brake controller is fairly easy if you are familiar with running wiring. To install a brake controller like the popular Tekonsha Prodigy P3 #90195 you will need to run the wires on the pigtail to the following…

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Answer 6

Either way is correct. It depends on if you want to keep the semi-style 7-Way (if you need to tow that type of trailer) or if you will never be towing a semi-trailer. If you need to keep the 7-Way semi active on the truck, then you would need to…

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Answer 7

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 8

There are a number of factors involved when converting a semi 7-way to an RV 7-way. Semis generally use a 7-pin round pin socket, similar to #PK11720. And RV style 7-way uses blades, like #PK12706. We do not offer any pre-made adapters to make this…

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Answer 9

I have a solution for you but part #AKEBRK-10 is not what you are looking for. Instead the Dexter Electric Trailer Brake Kit Left/Right Hand Assemblies part #23-438-439 is the set you need. The others are just a little too narrow for your…

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Answer 10

To make the conversion, you'd need an electric over hydraulic brake actuator, the specific one depending on if you have disc or drum brakes. You'd want to use the HydraStar #HBA-12 for drum brakes or HydraStar #HBA16 for disc brakes.…

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Answer 11

State laws for trailer safety chains do vary a bit. In Indiana safety chains are required when pulling a 5th wheel trailer with a gooseneck hitch and any adapter. You may prefer to use chains like #RM3230 just for their safety margin, even if not…

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Answer 12

Yes, the 7-Pin Round connector is wired differently than the 7-Way flat RV connector. I will list the typical heavy duty truck wiring connections inside the plug on the trailer side for you. At the index guide for plugging the trailer end in to the…

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Brake Controller Recommendation for a Truck with Air Brakes and a Trailer with Electric Brakes

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