Erratic battery volts
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 801
Likes: 17
From: Middletown Delaware
Erratic battery volts
Ok when I start car cold battery volts at 14.2 on gauge. When car warms up the voltage goes erratic and low. I have cleaned grounds and checked starter & alternator connections. With a meter I have steady 14.2 v output at alternator. 14.2 at the starter, 13.2 input at battery. 12.7v or lower on gauge in car and its erratic. Digital in car and analog look the same. I did some research am I looking at a bad ignition switch. Also headlights are intermintant to open but this may have to due to erratic volts. any suggestions. 99FRC 30,000miles Dave
Last edited by Dave Witman; Mar 18, 2010 at 11:36 AM.
Tech Contributor
Joined: Jan 2007
Posts: 19,454
Likes: 1,163
From: Dyer, IN
Ok when I start car cold battery volts at 14.2 on gauge. When car warms up the voltage goes erratic and low. I have cleaned grounds and checked starter & alternator connections. With a meter I have steady 14.2 v output at alternator. 13.4 input at battery. 12.7v or lower on gauge in car and its erratic. Digital in car and analog look the same. I did some research am I looking at a bad ignition switch. Also headlights are intermintant to open but this may have to due to erratic volts. any suggestions. 99FRC 30,000miles Dave
Drifting
Joined: Apr 2007
Posts: 1,998
Likes: 33
From: somewhere in New Hampshire
Mine was also erratic, voltage would always be fluctuating on the DIC and my radio display would flicker sometimes. Tightened/cleaned the battery terminals and problem solved! I hope something this simple fixes your problem as well. 
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 801
Likes: 17
From: Middletown Delaware
OK voltage at the starter is also 14.2. I am loosing a volt between starter and battery. Have not cleaned starter leads yet. A little tight in there with headers but that is my next step. Dave
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 801
Likes: 17
From: Middletown Delaware
Thanks guys its fixed. I cleaned and tightend connections at starter and all is well. The connections looked like new but I guess not. I now have a .2v drop at battery the digital read out is steady at 14.2 and the headlights work every time. Dave
Tech Contributor
Joined: Jan 2007
Posts: 19,454
Likes: 1,163
From: Dyer, IN
