Semi Truck Diagnostic & Testing Tools

Semi Truck Diagnostic & Testing Tools

Featured Brands

  • Dorman® - 10' Test Leads
    Dorman® - 10' Test Leads (84610)
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    # mpn2453793
    Universal 10' Test Leads by Dorman®. Dorman's retractable test leads are indispensable for having on hand in the shop or the garage. Save time by keeping them visible and available: the magnetic backing on the case firmly affixes to...
    Essential for reliable testing of electrical circuitsEasy to use
    $7.82
    In Stock - Ships within 24 hrs
  • Dorman® - 12 V Alternator and Battery Tester
    Dorman® - 12 V Alternator and Battery Tester (84502)
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    # mpn2343790
    Universal 12 V Alternator and Battery Tester by Dorman®. Dorman offers a comprehensive line of Electrical Multi-Testers for almost any automotive repair. All Electrical Multi-Testers are constructed of high-quality materials for...
    Testers light up and/or buzz to indicate testing resultDurably designed for a long service life
    $6.76
    In Stock - Ships within 24 hrs
  • Dorman® - 12 V Circuit Tester with LCD Display
    Dorman® - 12 V Circuit Tester with LCD Display (88058)
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    # mpn1296822558
    Universal 12 V Circuit Tester with LCD Display by Dorman®. Dorman offers a comprehensive line of Electrical Multi-Testers for almost any automotive repair. All Electrical Multi-Testers are constructed of high-quality materials for...
    Testers light up and/or buzz to indicate testing resultDurably designed for a long service life
    $12.21
    In Stock - Ships within 24 hrs
  • Dorman® - 15" Multi Purpose Ground Strap
    Dorman® - 15" Multi Purpose Ground Strap (60213)
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    # mpn2453783
    Universal 15" Multi Purpose Ground Strap by Dorman®. Dorman offers a line of Body Electrical Ground Straps for a wide range of applications. All Body Electrical Ground Straps are constructed of high-quality materials for long-lasting...
    Strap measures 15" in length to cover most usesMade of copper for high conductivity
    $4.11
    In Stock - Ships within 24 hrs
  • Dorman® - 3/8" Copper Ring Lugs with Insulation
    Dorman® - 3/8" Copper Ring Lugs with Insulation (86184)
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    # mpn2453810
    Universal 3/8" Copper Ring Lugs with Insulation by Dorman®. Dorman offers a comprehensive line of Copper Lugs for almost any automotive repair. All Copper Lugs are constructed of high-quality materials for long-lasting durability.
    Conveniently packaged in a variety of piece counts to assist with both small and large projectsAlso suitable for a broad range of industrial and commercial uses
    $2.32
    In Stock - Ships within 24 hrs
  • Dorman® - 399-piece Automotive Electrical Repair Kit with Case
    Dorman® - 399-piece Automotive Electrical Repair Kit with Case (86689C)
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    # mpn1296821953
    Universal 399-piece Automotive Electrical Repair Kit with Case by Dorman®. Electrical Diagnostic and Repair Kit contains an assortment of the most popular items needed to complete electrical repairs. Conveniently packaged in a reusable...
    A cost-efficient and time-saving alternative to purchasing each component separatelyConveniently packaged in a durable plastic tray for protected storage
    $38.39
    In Stock - Ships within 24 hrs
  • Dorman® - 9" Computer Safe Test Probe
    Dorman® - 9" Computer Safe Test Probe (86602)
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    # mpn1296821933
    Universal 9" Computer Safe Test Probe by Dorman®. For accurate testing of voltage and amperage sensitive circuits, use Diagnostic Test Probes. Replacement is constructed of high-quality materials for durability and a longer service life.
    Quality plastic, copper, and aluminum constructionSafe to use on computer controlled circuits
    $21.27
    In Stock - Ships within 24 hrs
  • Dorman® - In-Line Spark Checker
    Dorman® - In-Line Spark Checker (86579)
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    # mpn2455580
    Universal In-Line Spark Checker by Dorman®. Test electrical circuits with confidence using this multi-function electrical tester. Made to test a variety of electrical parameters, it is constructed of quality materials to deliver...
    Durable construction - this electrical multi-tester is made from quality materials to ensure reliable resultsVersatile shop tool - this multi-function tester can be used to confirm a variety of electrical system parameters
    $6.47
    In Stock - Ships within 24 hrs
  • Dorman® - Un-insulated Alligator Clip Leads
    Dorman® - Un-insulated Alligator Clip Leads (85654)
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    # mpn2454221
    Universal Un-insulated Alligator Clip Leads by Dorman®. Dorman offers a comprehensive line of Alligator Clips for almost any automotive electrical repair. All Alligator Clips are constructed of high-quality materials for long-lasting...
    Many different lengths availableConveniently packaged in a variety of piece counts to assist with both small and large projects
    $1.97
    In Stock - Ships within 24 hrs
  • EZRed® - Windshield Washer Fluid Hydrometer
    EZRed® - Windshield Washer Fluid Hydrometer (S104)
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    # mpn4746917847
    Universal Windshield Washer Fluid Hydrometer by EZRed®. Test your engine’s cooling system with this easy-to-use and reliable tester to prevent freeze-ups in cold weather and boil-overs during hot conditions and ward off corrosion to...
    Tests methanol solutionsTemperature compensating
    $10.78
    In Stock - Ships within 24 hrs
  • Electronic Specialties® - 12 V Battery Load Tester
    Electronic Specialties® - 12 V Battery Load Tester (700)
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    # mpn4841267951
    Universal 12 V Battery Load Tester by Electronic Specialties®. The #700 has an internal loading capacity of 100 amps. It is a great tool for finding batteries that can’t stand up to the load of today’s automotive accessories. It...
    Internal 100 Amp loading capacityTests battery voltage, relative starter currentwith heat protection draw, charging voltage and battery condition
    $29.07
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - 12 V Digital Electrical System and Battery Tester with Printer
    Electronic Specialties® - 12 V Digital Electrical System and Battery Tester with Printer (726)
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    # mpn1452539301
    Universal 12 V Digital Electrical System and Battery Tester with Printer (726) by Electronic Specialties®. An accurate battery and electrical 3 in 1 system tester (6 & 12 Volt Battery Tester+12V Start/Stop Battery Test, 12 & 24 Volt...
    Wide Testing Range from 40 to 2,000 CCABuilt-in Printer - print the results for permanent service record
    $224.00
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - 12 V Pro Relay Tester
    Electronic Specialties® - 12 V Pro Relay Tester (191)
    0
    # mpn1862129
    Universal 12 V Pro Relay Tester by Electronic Specialties®. Relay Buddy is a quick go / no-go tester for the most common automotive relays. With the included adapters, Relay Buddy now tests 5 different relay types and also tests...
    Designed for your maintenance needsMade from high-grade material for a long lifespan
    $124.18
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - 12 V Relay Tester
    Electronic Specialties® - 12 V Relay Tester (190)
    0
    # mpn1862128
    Universal 12 V Relay Tester by Electronic Specialties®. Relay Buddy is a quick go / no-go tester for the most common automotive relays. It provides you with an indication of the general health and functioning of the relay switch...
    Quick off-the-car relay testerChecks relay coil and switch contacts
    $53.93
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - 2 Pieces Replacement Thermal Printer Papers
    Electronic Specialties® - 2 Pieces Replacement Thermal Printer Papers (726-1)
    0
    # mpn4642933429
    Universal 2 Pieces Replacement Thermal Printer Papers by Electronic Specialties®. Your electrical system maintenance will be easier with this high-quality product. It is specially developed and manufactured for your electrical system...
    Designed to help to get your job done rightManufactured utilizing the highest quality materials
    $4.85
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - 70-Piece Diagnostic Test and Terminal Set
    Electronic Specialties® - 70-Piece Diagnostic Test and Terminal Set (846)
    0
    # mpn4745353489
    Universal 70-Piece Diagnostic Test and Terminal Set by Electronic Specialties®. Your electrical system maintenance will be easier with this high-quality product. It is specially developed and manufactured for your electrical system...
    Clear storage case included & helps you stay organizedWorks with Multimeters and digital scopes
    $143.78
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Digital Tach/Advance Timing Light
    Electronic Specialties® - Digital Tach/Advance Timing Light (125)
    0
    # mpn4794040149
    Universal Digital Tach/Advance Timing Light by Electronic Specialties®. This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers in mind. It will meet...
    Professional Timing Light with High Visibility LED display Very bright display indicates Tach (RPM) Degrees AdvanceBrilliant Xenon flash at all speeds
    $81.39
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - EZ Tach +Plus™ Automotive Tachometer
    Electronic Specialties® - EZ Tach +Plus™ Automotive Tachometer (328)
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    # mpn4745353483
    Universal EZ Tach +Plus™ Automotive Tachometer by Electronic Specialties®. If you're looking for a reliable solution to complete your project, this 1st-grade product is right up your alley. Designed utilizing the finest materials, it...
    Versatile instrument can measure RPM on a wide variety of engines from string trimmers to automotive.Reads engine revolutions from 0 to 20,000 RPM
    $51.08
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Essentials Of Electrical Power Generation
    Electronic Specialties® - Essentials Of Electrical Power Generation (183)
    0
    # mpn1862127
    Universal Essentials Of Electrical Power Generation by Electronic Specialties®. This is Dan Sullivan's 2nd book, which covers everything you need to know regarding Electric Power Generation from RV generators to large Gensets. Dan lends...
    Designed for your maintenance needsMade from high-grade material for a long lifespan
    $39.19
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Fuse Buddy™ 0 to 48 V Professional Fuse Tester Kit
    Electronic Specialties® - Fuse Buddy™ 0 to 48 V Professional Fuse Tester Kit (310)
    0
    # mpn4841267977
    Universal Fuse Buddy™ 0 to 48 V Professional Fuse Tester Kit by Electronic Specialties®. Your electrical system maintenance will be easier with this high-quality product. It is specially developed and manufactured for your electrical...
    Quick and easy way to check circuit amperage drawsCheck blower motor and fuel pump amperage draws
    $79.22
    In Stock - Ships within 24 hrs
  • Electronic Specialties® - Fuse Buddy™ 12 V/24 V Relay Tester
    Electronic Specialties® - Fuse Buddy™ 12 V/24 V Relay Tester (316)
    0
    # mpn4745353499
    Universal Fuse Buddy™ 12 V/24 V Relay Tester by Electronic Specialties®. Your electrical system maintenance will be easier with this high-quality product. It is specially developed and manufactured for your electrical system...
    Is it a circuit problem or a relay problem?Relay Fuse Buddy can help diagnose the case
    $81.72
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Fuse Buddy™ 30 A Mini Tester
    Electronic Specialties® - Fuse Buddy™ 30 A Mini Tester (305M)
    0
    # mpn1452539242
    Universal Fuse Buddy™ 30 A Mini Tester by Electronic Specialties®. Your electrical system maintenance will be easier with this high-quality product. It is specially developed and manufactured for your electrical system maintenance...
    Great for motor blowersOriginal fuse is replaced in-line during testing, thereby maintaining circuit protection
    $27.60
    In Stock - Ships within 24 hrs
  • Electronic Specialties® - Fuse Buddy™ ATC Current Loop
    Electronic Specialties® - Fuse Buddy™ ATC Current Loop (308B)
    0
    # mpn1862123
    Universal Fuse Buddy™ ATC Current Loop (308B) by Electronic Specialties®. Just clamp your current probe over the loop to access the amperage draw through a fused circuit. Easy testing access, plugs right into fuse socket, no more hand...
    Designed to help to get your job done rightManufactured utilizing the highest quality materials
    $13.55
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Fuse Buddy™ Current Loop Kit
    Electronic Specialties® - Fuse Buddy™ Current Loop Kit (309A)
    0
    # mpn4712443160
    Universal Fuse Buddy™ Current Loop Kit by Electronic Specialties®. Your electrical system maintenance will be easier with this high-quality product. It is specially developed and manufactured for your electrical system maintenance...
    Plug in Fuse Buddy and read circuit amp drawsEasy test connection into fused circuits
    $32.99
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Fuse Buddy™ Mini Current Loop
    Electronic Specialties® - Fuse Buddy™ Mini Current Loop (307M)
    0
    # mpn1862319
    Universal Fuse Buddy™ Mini Current Loop (307M) by Electronic Specialties®. Just clamp your current probe over the loop to access the amperage draw through a fused circuit. Easy testing access, plugs right into fuse socket, no more...
    Designed to help to get your job done rightManufactured utilizing the highest quality materials
    $13.55
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Inductive Pick-Up Timing Light
    Electronic Specialties® - Inductive Pick-Up Timing Light (150)
    0
    # mpn4794040285
    Universal Inductive Pick-Up Timing Light by Electronic Specialties®. This hard working timing light is accurate up to 8,000 RPM. An extremely bright flash will help you time the engine. The break and shock resistant plastic housing,...
    Inductive pick-up clamps over the spark plug wire - no adapters requiredPrecision focused flash tube for concentrated brilliant light
    $46.34
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - LOADpro™ 12 V/48 V Dynamic Test Leads
    Electronic Specialties® - LOADpro™ 12 V/48 V Dynamic Test Leads (185)
    0
    # mpn4686459962
    Universal LOADpro™ 12 V/48 V Dynamic Test Leads by Electronic Specialties®. This new version of LOADpro is capable of loading circuits as high as 48 volts. 185 can be deployed on Electrical System ranging from 12 volts up to 48 volts....
    Use on 12V to 48V circuitsPerforms voltage drop test with the push of a button
    $60.11
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Reflective Tapes for 330 and #332 Tachometers
    Electronic Specialties® - Reflective Tapes for 330 and #332 Tachometers (654)
    0
    # mpn4745353458
    Universal Reflective Tapes for 330 and #332 Tachometers by Electronic Specialties®. This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers in mind. It...
    Electronic Specialties 654 Reflective Tape for #330 and #332 - ESI65410 pack of reflective tape for ES brand photo tachometers - #330 and #332
    $11.90
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Relay Buddy™ 12 V/24 V Pro Relay Tester
    Electronic Specialties® - Relay Buddy™ 12 V/24 V Pro Relay Tester (192)
    0
    # mpn1452539233
    Universal Relay Buddy™ 12 V/24 V Pro Relay Tester by Electronic Specialties®. Relay Buddy 12/24 is a quick go / no-go tester for the most common automotive relays. This new version Relay Buddy tests both 12 and 24 volt relays. If the...
    Quick off-the-car relay testerChecks relay coil & switch contacts
    $61.13
    In Stock - Ships in 24 to 48 hrs
  • Electronic Specialties® - Relay Buddy™ 12 V/24 V Pro Relay Tester Kit
    Electronic Specialties® - Relay Buddy™ 12 V/24 V Pro Relay Tester Kit (193)
    0
    # mpn1437055644
    Universal Relay Buddy™ 12 V/24 V Pro Relay Tester Kit by Electronic Specialties®. Relay Buddy 12/24 Pro Test Kit tests five different relays. Relay Buddy is a quick go / no-go tester for the most common automotive relays and this new...
    Quick off-the-car relay testerChecks relay coil & switch contacts
    $135.28
    In Stock - Ships in 24 to 48 hrs




With today’s high-tech computer and electronics packed vehicles, electronic testers and diagnostic equipment have become the main weapons in the vehicle service arsenal, so we’ve stocked our digital shelves with scan tools, multimeters, analyzers and much more. When you’re armed with these electronic tools, you’ll be able to defeat any CHECK ENGINE light, blown fuse, balky window, recalcitrant alternator, or any other electrical malfunction with ease.

Electronic testers range from simple jumper wires, also called test leads, to sophisticated engine scan tools. Test leads allow you to bypass a circuit and directly test a component by applying 12 volts from the battery. Test lights, also called circuit testers, are essential tools for determining whether voltage is present at particular points in circuits. There are circuit powered and self-powered test lights, also known as continuity testers.

Test lights can tell you whether voltage is present, but they can’t tell you how much. For specific values you need a voltmeter, which is routinely packaged with an ohmmeter and ammeter in an electronic tester called a multimeter. There are analog meters that have a needle and a scale, but Digital Multi-Meters (DMM), also known as Digital Volt Ohm Meters (DVOM) are necessary for computer controlled circuits. Voltmeters can display the amount of voltage, such as when testing a battery or charging system, and test voltage drop. Ohmmeters measure resistance in a circuit and ammeters measure current flow.

A scan tool provides access to your vehicle’s computer control system via a cable connected to the Data Link Connector (DLC). With a scan tool you can read the Diagnostic Trouble Codes (DTCs) that cause CHECK ENGINE, Air Bag, and ABS dash lights to illuminate. Tool capability varies, and some can also read, record, and playback sensor data, display I/M monitor status, read and display freeze frame data, download to a PC, and be updated via USB port. In addition to erasing DTCs, some scan tools can also be used to reset oil lights and other warning lights.

Along with the above mentioned essentials, we also have many more diagnostic time savers including noid lights to check fuel injectors, current probes to measure current without disturbing the circuit, battery testers, infrared thermometers for instantaneous temperature indication, inspection cameras for peaks into the smallest places, and much more. And if you have an older, pre-computer controlled vehicle we have the tools you need to make adjustments and keep your vehicle running right, like timing lights to check initial timing and timing advance, and dwell/tachs to set breaker points and idle speed.