Electrical Archives - Page 7 of 55 - UnderhoodService
Bench Testing Can Reveal If The Alternator Is The Problem

Today’s computer-controlled charging systems tailor the charging rate not only to the electrical demands on the battery and alternator, but also to changing driving conditions. That makes diagnosis much more difficult when something goes wrong. Alternators have one of the highest return rates of any repair part – often because of misdiagnosis.

AGM Batteries And Testing

Two of the greatest changes we’ve seen in starting/charging systems during the past few model years have been the expanded use of the Absorbed Glass Mat (AGM) battery as standard equipment and the accelerating pricing structures of both AGM and conventional flooded-cell batteries.

agm batteries testing featured
GM Battery Maintenance: Cold Weather Or Long Stand Time

Inside the battery, the electrolyte is generally composed of 35% sulfuric acid and 65% water. When a lead acid battery is inactive (not actively discharged and charged), the acid, being heavier than water, will settle toward the bottom. This leaves a low acid concentration near the top, and higher concentration at the bottom. This condition is referred to as acid stratification.

Using Your Oscilloscope: Current Ramp Test Ignition Coils

The diversity of modern ignition coil designs has made ignition oscilloscope analysis more difficult because many ignition coil waveforms deviate from the conventional norm. Consequently, oscilloscope diagnosis shouldn’t be considered a definitive test of ignition coil condition unless it can be compared with a known-good waveform.

ignition coil scope tip
Power Window Regulator Diagnostics

Before you start pulling a door panel on a vehicle to replace a window regulator, you might want to start looking at the repair information first. Most power windows are more than just an electric motor and switch that changes polarity.

power window regulator
Parasitic Drain: 2003 Chevrolet Tahoe

This month’s Diagnostic Dilemma concerns a 2003 Chevrolet Tahoe with a parasitic battery drain that leaves it with a dead battery. The first step in diagnosing a parasitic drain is interviewing the customer to determine the average number of days and the driving conditions under which the battery drains.

Serial Data Bus Diagnostics

Serial data buses help eliminate multiple sensors and wiring. One sensor can share information with multiple modules without having to connect directly to the multiple modules. Serial data buses may seem like a daunting concept to some technicians, but understanding them is now a required skill to work on most modern vehicles.

Throttle-By-Wire Codes: P1512 On 2002 GMC Envoy

The PCM continuously monitors the commanded and actual throttle positions. The commanded throttle position is compared to the actual throttle position based on accelerator pedal position and possibly other limiting factors, and both values should be within a calibrated range of the other.

GMC Envoy throttle by wire large
February 18 Is National Battery Day

On National Battery Day, February 18, do something nice for that trusted power source in your car! Clean it up, have it checked out and make sure it doesn’t die on you just when you’re depending on it. Use hashtag #NationalBatteryDay to tell us what you’re doing for your batteries on National Battery Day!

State-Of-Charge And Charging Systems Diagnostics On Late-Model GM Vehicles

On 2007 and up GM vehicles, using conventional battery and charging systems tests can prove inconclusive. This is because of GM’s Electrical Power Management (EPM) system designed to monitor and control the charging systems and send diagnostic messages to alert the driver of possible problems. The EPM system primarily utilizes existing on-board computer capabilities to maximize the effectiveness of the charging systems, manage the load, improve battery state-of-charge and life, and minimize the system’s impact on fuel economy.

The Science Behind Precious Metal Spark Plugs

With the need to comply with ever-increasing efficiency and emission standards, auto manufacturers have been racing to raise the bar in spark plug performance over the past three decades. The use of precious metals like platinum and iridium in the manufacturing of spark plugs, as opposed to the use of nickel, has resulted in plugs that can last much longer and offer better performance than the spark plugs in circulation prior to the mid-1980s.

Spark plugs
Selling Batteries: Use Cell Phone Battery Life As A Sales Tool

Consumers understand the importance of battery life. When 10% power is reached, some phones reduce screen brightness and turn the battery symbol red. You have a similar tool in your arsenal for testing car batteries, and it is conductance testing.