Q: Electrical short

asked by on

Put a new battery in my 89 Nissan pickup about six months ago. Everything has been fine. Last week I went to start it (I only drive it once a week) and the battery was dead. Charged the battery and it started. Let it sit for a day and the battery was dead again. Took the battery out and charged it. It is holding a charge while not in the vehicle. There's a short somewhere. Any ideas? Thanks, Vern

First measure the "total" parasitic load while the battery is connected (use ammeter or volt ohmmeter). Make a note of that. Ordinarily, you could have 20 to 50 milliamps or so of current draw to run the car alarm and security features. You’re looking for loads beyond that small normal current draw.

Using the main fuse box, systematically measure current draw circuit by circuit until you find the (hopefully) one circuit that has the excess current draw. Then you have to track down the component or wire on that circuit that is responsible for the excess current draw.

As a temporary measure, to solve the battery discharge issue while you are tracking down the wiring/component fault, you could always install a battery cut off switch on a battery post but when using such a switch you will lose your car alarm and might also cause stored info in PCM to be lost, necessitating a re-learn every time you run the car.

If you’re unable to pinpoint the issue, feel free to enlist one of our mobile technicians who can come to your home to diagnose your draining battery and help you fit it accordingly.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Electrical short

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Wheres the 89 grand marquis fuse box location?

There is a fuse box below and to the left side of the steering column. That fuse box is covered by an access door that is part of the dash. In addition, there is a fuse box in the engine...

Q: Car was low on gas and shutoff on way to gas station and once i took key out it continued to try to start until battery died

Claimed by Jeff Engstrom

Q: Speedometer not working

Hello. In order to more specifically answer your question, I would require your vehicle's make and model. Generally speaking, speedometers are usually controlled by a speed sensor, and in older models with an accompanying speedometer cable. If the speed sensor...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...