How to Bypass Electrical Hiccups

We find the right fix for a stubborn battery on a 1976 Toyota FJ40 project

by

Words and Photos by Bryan Irons

Many off-roaders have had their vehicle break down at one point or another, whether on a trail, on a highway or just down the street from their home. Not everyone has days on end to repair these automotive SNAFU’s. And if the problem is an electrical issue the level of difficulty moves up a tier.

In my past life as a certified electrician and an off-road enthusiast in my current one, it’s been my experience that there isn’t an off-road or automotive guide, such as “electrical troubleshooting for dummies”, worth paying a penny for. There just isn’t an efficient guide to follow when it comes to sorting out electrical issues or dealing with the numerous types of electrical problems that can arise.

Trust me. Troubleshooting electrical issues successfully takes experience to narrow down the possibilities of error – all in a logical order. A good start, however, is understanding the type of metering equipment to use and how to use it. A reliable multi-metre is a great tool to have at home or in your vehicle. It’s important to learn how to measure voltages and resistances, know where your leads need to be plugged in, and what setting (s) you are required to use. Plus, learning how to do this on the trail may get you home in the event of an electrical failure.

Our multi-metre of choice is a Klein Tools CL800. Some key features include a voltmeter for measuring voltage potential, an ohmmeter for determining resistance, and a large clamp that indicates AC and DC currents. Another advantage is the price. We bought ours from Summit Racing for $172 CAD.

We also like using a Power Probe kit to find all the demons within electrical systems. The probe is an automotive wiring and troubleshooting tool that’s used as a ground source or a 12V DC electrical source. It comes complete with a built-in circuit breaker to keep from frying anything down the line. Although it’s not as universal as a multi meter like the CL800, it’s great for tracing wires, testing lamps, circuits, and finding common hiccups. We keep our kit close at hand and it costs anywhere from $120 CAD for a basic kit to $340 CAD to our master kit shown here.

Short of getting into an exceedingly boring electrical fundamentals course (there are no other kinds), we’re going to use the “water” analogy to explain some of the aforementioned electrical lingo.

Basically, think of electricity as water flowing through a pipe. The pressure of the water can be considered the voltage and the volume of water can be viewed as electrical current. Any restrictions in the line can be viewed as electrical resistance. Again, this is very rudimentary and not all things relate across cleanly, but if you use the water-in-a-pipe analogy to root out electrical gremlins, it will get you by in most circumstances.

The Tools and Effective Trouble Shooting

Back to troubleshooting. In one circumstance we had to track down an electrical problem with the battery in our 1976 Toyota FJ40 project rig, ‘Tim Toyota.’

The troubleshooting process could have been made easier if the electrical system of the Toyota was not in such disarray. Our ambition to rewire the entire rig was at an all-time low. We decided to deal solely with the electrical hiccups. Just recently, the Toyota’s battery kept dying after it sat for a few days. It was becoming an annoying case of Deja-vu and it inevitably required our attention.

Here’s the problem, some of the tools we used, and how we did it:

1. Our Klein Tools CL800. This can be found in just about any electrician’s arsenal. They are tough and reliable. What makes it a winner is its ability to read DC currents with its clamp. This is typically reserved for AC currents only. Some added bonuses include a thermocouple for reading temperatures, and a quality set of test leads for reading resistances and voltage.

2. Our beloved Power Probe. A great tool for sourcing power and to test any low current automotive electrical device, it can also read voltage and create an artificial ground point. The catch to using the Power Probe as a voltage source is you need a working battery or other source of power. Our master kit includes a slew of accessories and lead lengths long enough to reach around the longest of off-road rigs.

3. The Power Probe Lamp Adapters are perfect for troubleshooting burnt out turn signal relays and switches. Its instruction manual has plenty of information on what each of the numerous accessories can be used for.

4. Our dead battery. After charging it, we didn’t have any issues unless the rig sat for a few days.

5. The first thing we did was to see if we had a bad battery or a drain on the battery. This is where the CL800’s DC current measurement capabilities with its clamp were handy. With the clamp on the negative battery post (positive could be used as well) we were able to see (with the ignition ‘off’) we had a draw of 190 milliamps. In reality, we would’ve liked to see less than 35 in a new vehicle with multiple systems and running in the 'off’ position.

6. In order to trace down where our current draw was coming from, we started pulling fuses one by one until our current draw either was reduced to an acceptable level or completely gone. In our case, the draw was completely gone once we pulled power to the radio. Eureka. We’re on to something.

7. After pulling the radio, we used our power probe to start the radio up. Typically, there is a main power wire and a switched power leg used to turn the unit on (when the key is in the “on” position). With the radio main wire powered up, we were reading the almost 200 milli amps using our Klein clamp. We had a bad radio. After replacing it, we’ve not had a dead battery since.