• 2021

Crank it Up!

BATTERY AND STARTER TESTING AND REPLACEMENT

You cannot drive your vehicle if you cannot start it. And, you cannot start it without a functional battery. The starter and battery go hand-in-hand. Old batteries just can’t handle the job of starting your vehicle in cold winter conditions, regardless of the condition of the starter. Likewise, a bad starter with a good battery won’t get the job done either.

TESTING BATTERIES AND STARTERS

The battery is designed to provide a safe, efficient, reliable and mobile means of delivering and storing electrical energy. This electrical energy is required to operate the engine starting system, as well as to operate other vehicle accessory systems for limited durations while the engine and/or the charging system are not operating. The battery system is also designed to provide a reserve of electrical energy to supplement the charging system for short durations while the engine is running and the electrical current demands of the vehicle exceed the output of the charging system.

In addition, it provides ignition-off draw current. A normal vehicle electrical system will draw from five to thirty-five milliamperes (0.005 to 0.035 ampere) with the ignition switch in the Off position, and all non-ignition controlled circuits in proper working order. Up to thirty-five milliamperes are needed to enable the memory functions for the Powertrain Control Module (PCM), digital clock, electronically tuned radio, and other modules which may vary with the vehicle equipment.

The Midtronics GR8 battery tester is designed to help diagnose the cause of an inoperative battery. After the battery has been charged to an open-circuit voltage reading of 12.4 volts or greater, retest the battery with the Midtronics GR8, or equivalent, battery tester. The tester indicates if the battery is OK or if it is necessary to perform a load test to determine the battery cranking capacity. If the battery passes a load test, return the battery to service. If the battery fails a load test, it is faulty and must be replaced.

The voltage drop test is a series of tests that are performed using a voltmeter (accurate to 0.10 volt) to determine the serviceability of the battery cables. A bad battery cable is often easy to detect (see Figure 1).

Figure 1

Figure 1

Cable terminals that display corrosion can be cleaned easily with the proper cleaning tools, such as the one shown in Figure 2. Clean the battery cable terminal clamps ② of all corrosion. Remove any corrosion using a wire brush or a post and terminal cleaning tool ①, and a sodium bicarbonate (baking soda) and warm water cleaning solution.

Figure 2

Figure 2

The positive and negative cables might appear to be clean and good, but the cable and/or connection(s) might be bad and in need of repair. This is where the voltage drop test comes in handy. It tests the cable connection between the positive post and positive cable, the negative post and negative cable, the battery positive cable terminal clamp and the starter solenoid B(+) terminal stud and negative cable terminal clamp and a good clean ground on the engine block.

TEST #1 Connect the positive lead of the voltmeter to the battery negative terminal post. Connect the negative lead of the voltmeter to the battery negative cable terminal clamp. Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If voltage is detected, correct the poor connection between the battery negative cable terminal clamp and the battery negative terminal post.

TEST #2 Connect the positive lead of the voltmeter to the battery positive terminal post. Connect the negative lead of the voltmeter to the battery positive cable terminal clamp. Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If voltage is detected, correct the poor connection between the battery positive cable terminal clamp and the battery positive terminal post.

TEST #3 Refer to Figure 3. Connect the voltmeter ② to measure between the battery positive cable terminal clamp ① and the starter solenoid B(+) terminal stud ③. Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If the reading is above 0.2 volt, clean and tighten the battery positive cable eyelet terminal connection at the starter solenoid B(+) terminal stud. Repeat the test. If the reading is still above 0.2 volt, replace the faulty battery positive cable.

Figure 3

Figure 3

TEST #4 Connect the voltmeter to measure between the battery negative cable terminal clamp and a good clean ground on the engine block. Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If the reading is above 0.2 volt, clean and tighten the battery negative cable eyelet terminal connection to the engine block. Repeat the test. If the reading is still above 0.2 volt, replace the faulty battery negative cable.

Another battery test that can be performed is the open-circuit voltage test. This is a no-load test and will show the approximate state-of-charge of the battery.

Once the battery has been checked, the starter can be checked to see if it is the cause of the no-start problem. The two most common tests are the cold cranking test and the feed circuit test. The cold-cranking test will show if a cold engine will increase the current draw and reduce the battery voltage reading, as it should happen. Next, perform the feed circuit test which will determine if there is excessive resistance in the high-amperage feed circuit.

BATTERY AND STARTER REPLACEMENT

If it is determined that the battery and/or starter must be replaced, there are as many different procedures as there are models of vehicles.

What we have seen lately is the location of the battery elsewhere than in the engine compartment. And, because of front-wheel drive layouts, starters can be difficult to reach.

For example, the battery for the Chrysler 300 is hidden in the trunk below a panel. On the Jeep® Grand Cherokee, the battery ended up under the front passenger seat (see Figure 4). To remove it, move the seat forward and remove the cover to gain access. Just hope that it’s a power seat which can be raised. That gives you more clearance to remove the battery.

Figure 4

Figure 4

Our example vehicle for this article is the ever popular Dodge Caravan circa 2015. The battery is located in the engine compartment and is easily accessible. Remove the battery cable terminals, then loosen the holdowns to remove it. Before installing the new battery, be sure the battery tray is clean.

Replacing the starter is a bit more challenging (this only applies to the popular 3.6L V6 engine). First of all, the minivan must be raised and supported. With the Caravan, the catalytic converter must be removed. It should be noted that the converter removal process requires the removal of the cross-under pipe and the passenger side halfshaft, so there is some work involved in replacing the starter. Then, you remove the front engine mount-through bolt and the engine mount bracket. Finally, the starter can be removed. Installation of the new starter is the reverse process of the removal procedure.

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