Timesaving Troubleshooting Tricks

Tips that may actually help you come out ahead in your battle against the clock.


Grounds For Sanity
Ever encounter an onboard computer problem that seems to defy all your diagnostic logic, and the routines provided in shop manuals? If so, check to make sure that all grounds are clean and secure.

Why? The computer or one of its sensors may not be grounded properly, causing a difference in ground references and the amount of voltage being sensed. Since this difference can confuse the system, make absolutely sure that the gremlin you're chasing isn't just a bad ground.

Current Affairs
Have you ever experienced a no-charge problem, and replaced the voltage regulator, only to have the car come back with the same problem ... again?

If the windings of the alternator rotor should develop a short, their resistance drops. This reduced resistance causes current flow to increase through the field windings, and through the regulator's field control circuit. Since the transistor in the voltage regulator is only capable of handling a certain amount of current, the transistor will eventually fail from current overload.

That's why it's in your best interest to check the alternator's field-current draw when you face a car with a failed regulator. If current draw is too high (normal current draw is around 4 amps), you'll want to replace the alternator and the regulator - before it becomes a comeback.

Lost time can never be made up, but by heeding some of the examples given here, you just might be able to beat the clock every now and then.

Questions or comments about this article, contact the author, Dave Cappert, at dcappert@verizon.net.

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