I have been to a lot of car audio shops that use test lights, and not as many that use digital multimeters. Is one really “better” than the other for finding power sources?

Absolutely! A test light looks like a screwdriver with a sharp pointed end, and consist of a small bulb and a grounding wire or cable. It works by grounding the bulb, and once it comes in contact with a power source, it will complete the circuit and light the bulb. This is the easiest way to test power because the bulb either lights up for power or doesn’t if their isn’t any power.

The problem with using this type of testing on todays vehicles is the complexity of some of the circuits inside the dash. When you complete the test light circuit on a “hot” wire, you essentially create a small “arc” of electricity that can short some of the more sensitive equipment such as an air bag sensor or relay. I have actually seen one installer blow the airbags out of a new BMW M3 by testing wires with a test light. In most cases, it won’t cause any harm, but when it does the cost can be very high.

I highly recommend using a digital multimeter to test circuits. The are very accurate and can tell you a lot of useful information such as voltage, amps, and ohms, all of which are essential to know when building a good sound system.

These multimeters work a little differently than a standard test light. They typically have a battery on board to power the meter, so they don’t pull power from the power source, reducing the tendencies to “arc” the power source. They are generally safer to use on sensitive systems than their test light counterparts for this reason.

Digital Multimeters are a great tool for car audio installers, as they can help track down problems in the system. They are also a must have when installing any other 12 volt auto accessories. A test light will light up under power, but wont tell you if you are getting the proper voltage and amps. With a multimeter, you can start at the component taking readings, and work your way backwards until you find the component that is not functioning properly.

Multimeters range from about 10.00 to over 100.00, and depending on your level of work and how accurate you need to be, you can find one that will work for you. They are a great investment, and will save a lot of headache when you are problem solving a system.

Jaguar XK 140: Filling the Spot Between the 120 and the 150

Looking at its power source, the Jaguar XK 140 has a more powerful engine than the Jaguar XK 120. The engine of the former is a 190 bhp engine. It also holds a rack and pinion steering plus an optional Special Equipment pack that includes wire wheels as well as more power that is actually some 210 bhp. The production for the Jaguar XK 140 ended after three years starting from its production when the newer Jaguar XK 150 arrived at the scene.

The body styles that were available for the Jaguar XK 120 were also made available for the Jaguar XK 140. Since the Jaguar XK 140 is a sports car, the body styles made available for the consumers included the roadster that was a two seater style with side screens, a detachable windshield, and a hood. There also was the Drop Head Coupe, which was also known as the DHC. It had a fixed windshield, wind up windows, 2 + 2 seating, and an attached hood. The last body style for the Jaguar XK 140 was the Fixed Head Coupe. This was also called the FHC. It held a 2 + 2 seating, along with some wind up windows. Like the Jaguar XK 120, the Jaguar XK 149 body styles FHC and DHC still continues to hold dashboards and door cappings covered in walnut wood. The roadster, on the other hand, has a leather covered dash, padding on the top of its doors, and side screens for weather protection. The Jaguar XK 140 was also made available with different color choices for its exterior. The list of colors included suede green, pastel green, British racing green, pacific blue, pastel blue, birch gray, battleship gray, lavender gray, dove gray, pearl gray, red, maroon, cream, and black.