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137 Output Tester

The Lite-Check, 137 Truck and Trailer Output Tester is the simple to use tool that provides technicians with accurate output readings for commercial trucks, trailers, and dollies. Simply attach the included 7-way cable and glad hands to the output receptacle of the vehicle and technicians are presented with accurate air and electrical readings via the LCD 4.75” X 1.75” screen.

Product Description

Electrical Output Testing

Since the 137 Truck and Trailer Output Tester is powered by the vehicle it’s plugged into, it has an initial automatic pass/fail electrical test. If the tester fails to power on, the tractor, trailer, or dolly does not have sufficient electrical voltage to power the tester or a trailer ABS ECU.

While attached, and with sufficient electrical voltage, the tester provides up to 15 amperes of load to the incoming system simulating the lighting system of a trailer. This provides easy testing for weak or malfunctioning breakers in the vehicle. Additionally, the tester triggers the in-cab ABS lamp just as a faulty ABS ECU would. This provides an immediate test of the operability of the lamp without the need for a trailer. Accurate amperage and voltage output is displayed on the LCD display and technicians can use this data to identify possible electrical loss when connecting multiple trailers and dollies.


Air Output Testing

The 137 Truck and Trailer Output Tester also provides easy testing of tractor, trailer and dolly air systems. Equipped with two easily read pressure gauges which accurately display air pressure output. These gauges have highlighted areas to show the ideal working zones.

The emergency pressure gauge also has a reading of 55 PSI highlighted to identify when the Air Warning System should be triggered. Issues with the Air Warning System may be identified if during an emergency air loss test the alarm is not sounded by the time the pressure reading has dropped to 55 PSI point.

Tests The Following

Tractor Output Test: No Load, Tractor Output Test: Full Load, Air System Testing, Preventative Maintenance Inspections, Analog Pressure Gauges, Circuit Identification, Lighting & Electrical Circuit Testing, Assess Available Power

Product Warranty Information

LITE-CHECK products have a one-year limited warranty on parts and labor against manufacturing defects. All warranty services are to be performed at LITE-CHECK, Spokane, Washington. The customer is responsible for shipping costs.


There are no accessories for the 137 Output Tester. 


Dimensions and Specifications


The tester is designed for negative ground vehicles (black-negative, red-positive). In case of reversed battery leads on the power cable, the tester will not operate.

Power Supply Set Up:
Attach the battery cable clamps (or ring terminals) to a 12Vdc automotive battery, or a regulated power supply (such as the LITE-CHECK 311R).​ Turn the power switch located on the back panel of the tester on for operation.

Low Battery Messages:
NOTE: The tester will not work properly if the battery is not charged to a full 12+volts. The tester will not operate and will possibly lock up if the power is below 10.5 volts.

Features and Benefits

Free-Up Personnel and Equipment

The 137 Truck and Trailer Output Tester provides the ability for a single technician to accurately test the in-cab ABS lamp without requiring a full trailer for the test.

Automatically Assess Available Power

The 137 Tractor and Trailer Output Tester checks that there is enough electrical output from the tractor to adequately power the ABS ECU on a trailer.

Know Your Air Output and Warning System Work Properly

Easily test that the vehicle’s air output is sufficient for brake operation and that the tractor’s air warning system is triggered at the appropriate pressure.

Is There Enough Electricity to Operate the Lights and ABS?

The 137 Tractor and Trailer Output Tester is completely powered from the tractor, trailer, or dolly it is plugged into. This provides an automatic Pass/Fail condition for power output.