What Should the P2 Brake Controller Display when No Trailer is Connected

Question

Question:

Air brakes, what should the indicator reading on the on the underdash control while not towing, 0.0?

asked by: Anthony P

1

Helpful Expert Reply:

The P2 brake controller # 90885 should read nc if no trailer is connected. It would flash 0.0 if the power output is set to zero. I have linked the manual for the brake controller that includes this and other codes.

If you think there is a problem with the brake controller there are ways that you can test it, see links. If the trailer has air brakes then the controller will not work with them. If the vehicle has air brakes the brake controller will work provided it is wired in correctly.

If you are having a specific problem let me know what it is and any other details you can provide.

expert reply by: Michael H

1

Answer 1

If your trailer brakes activate when using the manual override but not when pushing on the brake pedal you may have a bad connection or a faulty brake switch. I have also linked below our article on Brake Controller Troubleshooting. Also if you have…

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Answer 2

First, make sure that your #3015-P harness is pinned out correctly. The red wire should be in the bottom left location (if looking at the back of the end that plugs into the truck). Directly next to the red wire should be the blue wire. Above the…

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Answer 3

While unlikely, it is certainly possible that the trailer battery could backfeed to your vehicle's battery when hooked up under the scenario you described. To make sure this doesn't happen all you need to do is add a single diode like the…

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Answer 4

From what I can tell of your explanation, it sounds like the trailer battery is backfeeding into the truck, causing this issue. The only way I can think of that this would happen is that your 7-way like the 7-Way Molded Trailer Wire Connector #H20043…

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Answer 5

In order for your truck battery to be able to charge your trailer battery it will have to have a connection to it that is going to have voltage like you tested. What you have is normal and the only possible downside would be if your trailer battery…

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Answer 6

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 7

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 8

The difference between the Class II and Class III hitches has to do with their Gross Trailer Weight (GTW), their Tongue Weight (TW), and their Hitch Receiver Size. Class II trailer hitch receivers have a 1-1/4 inch receiver and can be rated up to…

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Answer 9

To determine the size of the brake assemblies you need you have to measure the depth and width of the hub drum on the axle like what you see in the picture I attached. The most common size is 2-1/4 inch wide like the #T4071600-500 that you…

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Answer 10

If you just need a 4-pin to 7-pin trailer wiring adapter, then you can use part #C57672. This will plug into the 4-pin trailer connector on your brother's vehicle and give him the 7-pin socket for the trailer. Keep in mind, this will only give…

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Answer 11

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…

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Answer 12

Hey Richard, thanks for reaching out! The Dexter DX7.5 Drop-N-Go Brake Actuator #099-175-00 is a great option for a replacement actuator because it's a direct replacement for the common Model 60 actuators that were popular in the '90s.…

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