5 Automotive Diagnostic Tools From Harbor Freight To Add To Your DIY Collection

More than 200 years before Carl Benz built the world's first car, Sir Francis Bacon coined the phrase, "Knowledge is power."

Estimating the cost of auto repairs can be like guessing how many grains of sand are on a beach, however, and some fixes can run into the thousands of dollars, making some of that knowledge as painful as getting sand kicked in your eyes. 

Bacon's words certainly apply when you take your car in for repairs, as knowing what is wrong before talking to a mechanic gives you the power you need to keep money in your pocket. Diagnostic tools, whether they are mechanical or electric, can be a big help in providing you with that knowledge. Harbor Freight is nearing its 50th year in business and has more than 1,400 stores in the United States where you can buy all kinds of tools and equipment to repair and maintain your car or truck. 

Among Harbor Freight's offerings are many diagnostic tools that can provide you with the precious information that will help streamline the repair process, whether you're going to fix your vehicle yourself or take it to a professional. Here are five selections from Harbor Freight's catalog you'll want to have in your toolbox or garage for when your car starts behaving strangely.  

All cars and light trucks made in the USA since 1996 (and gas-powered vehicles in the European Union since 2001) use a standardized digital interface called OBD-II. OBD stands for On-Board Diagnostics; this system gathers information from your car's sensors and transmits it to a 16-pin connector, usually located under the dashboard. 

When your "Check Engine" light comes on, you can connect an OBD-II code reader, like the one from Cen-tech that Harbor Freight sells for $39.99, to read the system's codes and discover what is wrong.

This reader will display codes and oxygen sensor data in English, French, or Spanish and allow you to turn off that pesky dashboard warning light. It has a rubberized outer cover and works in temperatures from 32º to 122ºF. No batteries are required — it gets its power from your vehicle's battery via the No. 16 pin on the connector. The included printed manual has an index of common trouble codes, or you can look them up on the internet.   

For taking a look inside engine cylinders, fuel tanks, and other inaccessible spots, an inspection camera like this remote camera from Centech is invaluable. It retails for $79.99 and has a 2.4-inch screen with 320 x 240 pixels resolution. The camera runs on four AA batteries and comes with a video out cable with an RCA jack so you can connect it to an external monitor. 

The scope end is waterproof and just 8.5mm in diameter, so it will fit into most spark plug openings. The lens allows you to see objects as close as one inch, and the flexible cable is 38 inches long. It has an average rating of 4.3 out of 5 stars from nearly 1,400 Harbor Freight buyers, with 88% recommending it to others. Many reviewers mentioned that the scope fit easily inside the cylinders of their engines, and several buyers noted that they were pleased with the value this camera offered for the cost.

An electrical multimeter is a handy instrument for finding short circuits and testing batteries, alternators, and other electrical components. Harbor Freight carries a variety of multimeters, including the Ames DM600 digital multimeter. This meter retails for $42.99 and measures AC and DC voltage up to 600 volts. It also measures AC and DC current up to 10 amps and can test diodes, resistance, and household 1.5 and 9-volt batteries.

It can be used in temperatures from 32º to 104º Fahrenheit and environments of 80% relative humidity or less. This meter is powered by a 9-volt battery, which is included along with two test leads. It has a 2" LCD panel with a hold function to freeze result readings, a continuity test function with an audible buzzer, and a folding stand in the back for one-handed operation. Harbor Freight customers give it an average rating of 4.5 out of 5 stars, and 93% would recommend this meter to others.

If you have an older vehicle that allows you to vary the ignition timing by rotating the distributor, a timing light is critical to keep your engine running at its best. Proper timing ensures you'll get all the horsepower and fuel economy your engine is capable of and helps keep your vehicle's emissions as clean as possible. A timing light works by flashing in sync with the spark from your engine's No. 1 cylinder to illuminate a mark on the crankshaft pulley; by loosening the distributor's hold-down clamp and rotating the distributor, you can adjust the timing.

For $99.99, the Zurich digital timing light sold by Harbor Freight will allow you to do your own tune-ups and make adjustments when you drive to a higher or lower altitude. The clamp on this light fits plug wires up to 10mm in diameter, and the digital display doubles as a tachometer and allows you to read and adjust ignition dwell. It has an average customer rating of 4.5 out of 5 stars, and 90% of Harbor Freight buyers would recommend it to others. 

If you know your vehicle has sufficient spark, and the timing is set correctly, but it still won't start, the problem is likely with the fuel supply. In that case, the Maddox fuel injection service kit that Harbor Freight sells for $39.99 will help you diagnose issues with your fuel system. It includes a dual-scale gauge that reads pressure up to 100 PSI (700 kPA) and an assortment of fittings, hoses, and adapters for most vehicles. There is also a pressure relief valve with an attached hose to safely release pressure from your system and avoid troublesome sprays and leaks that could potentially cause a fire.

The kit includes everything you need to perform running, residual, rail and flow rate pressure tests and a molded plastic carrying case to keep all the pieces organized. It has an average customer rating of 4.7 out of 5 stars, and 97% of Harbor Freight buyers would recommend this test kit to others.