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

John S.

7/13/2024

90885 brake controller will not operate trailer brakes properly. Those brake controllers look for truck nose to dip to operate the proportional brake control which larger (with air brakes) truck do not do. Only an air over electric brake controller will operate brake properly, like the HA100400C

Reply

Lee

4/8/2025

I want to buy an H100400C When I search that number it comes up as a pencil hitch. Please help me find the controller

Reply

Jameson C.

4/8/2025

@Lee That brake controller is no longer available as it was discontinued.

Reply

Answer 1

To tow your trailer that uses an RV style 7-way blade style connector with your semi that has a 7-pin connector, you need to construct an adapter that will also combine the brake signal into the right and left directional signal pins. This can be…

view full answer...

Answer 2

Hey Anthony, Here at etrailer we have a controller or two that will do the opposite (take the air system from a tow vehicle and make it work with electric trailer brakes), but we don't have any controllers that will work with air brakes on the…

view full answer...

Answer 3

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…

view full answer...

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…

view full answer...

Answer 5

You do have the option to utilize the air brakes on your 2023 Freightliner Cascadia to control electric trailer brakes using the Hayes Air Actuated Trailer Brake Controller, part #HA100400C. However, we mostly recommend just using an electric brake…

view full answer...

Answer 6

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 the…

view full answer...

Answer 7

The globrite 122 in red or yellow/amber are 3.75 inches by 1.70 inches from what I can find online. We do not have a direct replacement, however the closest dimension we have to replace them is 3-1/2 by 1 inch. I recommend the #MC68RB and #MC68AB. If…

view full answer...

Answer 8

In order to haul your gooseneck trailer with a fleet of semi-tractors you will need to make your own adapter harness which will then make for a plug and play connection but they don't make anything pre-assembled for this out of the box to my…

view full answer...

Answer 9

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 make…

view full answer...

Answer 10

As long as you have electric brakes on your race car trailer the RF brake controller part #TK94FR will work well. On the RV you'd just need to have a 7-way trailer wiring harness like the #HM48480 with the turn signals all working properly and…

view full answer...

Answer 11

So you're wanting a king pin adapter that would take the place of your gooseneck coupler, is that correct? If that's the case, the best way to do that wouldn't be to add a pin box. You'd want to use a king pin adapter instead.…

view full answer...

Answer 12

I do see your Holland FW35 is designed to fit a 2" kingpin like the one used on both the 25K #KPG5-R25-IP and 30K #KPG5-R30IP coupler adapters you looked at. For the wiring you will need to create a custom adapter. First you will need the 7-Pole…

view full answer...

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

Products Referenced in This Question

Product Page this Question was Asked From

Featured Help Information

Instructions

Miscellaneous Media

Continue Researching