Do It Yourself - Automotive Electrical Schematic Diagnosis - Intermediate

Introduction

Description of Introductory Course Review

Review of the Basic Electrical fundamentals of What Every Circuit Needs

Review of the Series and Parallel Circuit Differences.

Review of the Horn Schematic Explaining the components and Operation.

Test your understanding with this quick quiz on Automotive Electrical Terms.

See if your diagnostic skills are improving with this diagnostic assessment. Download the Schematic and see if you are up to the challenge!

Let's go over the Schematic Quiz from Lesson 7 and see how you did.

Let's look at the similarities and differences of Power side and Ground side switches so we can understand them and later apply what we have learned to Information Circuits.

In this video, I will show you how to highlight Power Load and Ground in three colors on the Power side and Ground side switch circuits from video nine. This will help make the expected voltage readings stand out on the page so you can enhance your understanding.

If the Battery voltage changes when the car is running, how will this affect the voltage reading we expect at different parts of the circuit?

Let's take a look.

The Module Information Circuits are often misunderstood. In this video, I will show you how they are very similar to the Power side and Ground side switch circuits that you already understand.

The Computer or Modules on the car are the decision makers for various systems on the car. This video explains how the Input circuits, Module Circuits and Output Circuits work together.

The trunk release schematic in this lesson demonstrates the use of input, module and output circuits used on cars today.

Challenge time again.... See if you can highlight Power, Load and Ground for this Trunk Release Schematic. Download the schematic from the additional resources for this lesson.

The Trunk Release does not work. Let's do some schematic diagnosis and discuss how we would go about narrowing down the possibilities.

Here is another Fault where the Trunk Release does not work. Put on your detective hat and let's start narrowing down the possible suspects.

Let's use the diagnostic process again and see how we might reduce the number of steps necessary to complete the diagnosis.

The cooling fan system for this lesson includes five power, load and ground circuits and has three relays. Let's see how it works.

Highlighting the cooling fan schematic in the Off position can go a long way to helping you understand how the circuits operate.

This time let's highlight the cooling fan schematic with the fans in Low Speed. If you have not done so already, download the schematic in the additional resources.

One more time except this time let's highlight Power, Load and Ground when the fans are on High Speed. As we do our diagnosis in the upcoming lessons, you will see how important understanding the highlighting can be.

The Low Speed fans do not work, but the high speed fans do work. Let's look at the possible complaints we might hear from a car owner and see how we can diagnose the problem.

This time the Low Speed fan works but the High Speed fans do not work. Detective hat time again. Let's see how we can narrow down the possibilities and find the culprit.

Can a scan tool help us more quickly diagnose the problem?

None of the fans work this time. What do you think the complaint will be? How can we quickly narrow down the possibilities?

This video twists the diagnosis around to help you understand the schematic inside out. I call it reverse diagnosis.

This video provides a few tips to help you avoid a misdiagnosis when dealing with computers and modules.