Electrical Issues - Voltage Flucuations....
Thread Starter
Burning Brakes
Joined: Nov 2001
Posts: 783
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From: Statesboro Ga
Electrical Issues - Voltage Flucuations....
After a recent jump start, noticed that my 03 had random voltage fluctuations. When I first step on the brakes, head lights dim briefly then go back to normal for rest of braking then fine on getting going again. The gage lights inside (mainly radio) vary in brightness especially when first starting up. Sometimes during idle, it almost cuts off with hard wired radar detector blinking off then coming back on as if first turned on. Also, it's like going thru a reset with gas gage coming up on heads up when it hadn't been set there before the electrical blink.
Sometime last year I put in an Optima battery, and not too long ago had to get jump started after using car as radio while doing yard work. Had never had issue before. I thought Optima was supposed to be bad *** battery....
Not trying to ramble, but trying to give as many details as possible for yall to help me with troubleshooting. Thanks in advance!!!
Sometime last year I put in an Optima battery, and not too long ago had to get jump started after using car as radio while doing yard work. Had never had issue before. I thought Optima was supposed to be bad *** battery....
Not trying to ramble, but trying to give as many details as possible for yall to help me with troubleshooting. Thanks in advance!!!
Drifting
Joined: Sep 2009
Posts: 1,862
Likes: 594
From: Prescott, Arizona
If the battery is good, fully charged, and the terminals and ground clean and tight, listening to the radio for an hour or so should not result in a need to jump the car. The following may help figure out what's up:
Check for codes. The result may point you in a particular direction.
If you have a multimeter, check battery voltage at rest, engine off. You should see around 12.5 to 12.6 volts.
What is the voltage reading at the instrument cluster with the engine at idle? Look for over 13, probably 13-1/2 volts. Is it steady when revving the engine to 2,000 rpm?
The battery terminals must be clean and TIGHT. My Factory Service Manual says 12 foot pounds, the Optima Battery sheet says 11 foot pounds. You have to pull pretty hard on a 6" battery wrench to get this torque level.
If the above does not lead you to a solution, load test the battery.
Check, clean and dielectric grease all vehicle grounds, a significant effort.
Check for codes. The result may point you in a particular direction.
If you have a multimeter, check battery voltage at rest, engine off. You should see around 12.5 to 12.6 volts.
What is the voltage reading at the instrument cluster with the engine at idle? Look for over 13, probably 13-1/2 volts. Is it steady when revving the engine to 2,000 rpm?
The battery terminals must be clean and TIGHT. My Factory Service Manual says 12 foot pounds, the Optima Battery sheet says 11 foot pounds. You have to pull pretty hard on a 6" battery wrench to get this torque level.
If the above does not lead you to a solution, load test the battery.
Check, clean and dielectric grease all vehicle grounds, a significant effort.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
A weak or damaged battery and or improperly installed battery terminals can and usually causes voltage fluctuations like you are experiencing.
Take the battery out and fully charge it and then go have it fully tested for CCA and Reserve Capacity.
If it passes, clean the cable terminal ends and battery terminal pads and properly TORQUE the terminals to the battery @ 11 ft/lbs.
The voltmeter inside the car DOES NOT read battery voltage. It reads voltage after the ignition switch which can be a lot different than actual battery terminal voltage.
Take the battery out and fully charge it and then go have it fully tested for CCA and Reserve Capacity.
If it passes, clean the cable terminal ends and battery terminal pads and properly TORQUE the terminals to the battery @ 11 ft/lbs.
The voltmeter inside the car DOES NOT read battery voltage. It reads voltage after the ignition switch which can be a lot different than actual battery terminal voltage.
