Electrical

Tiny
HANDYMAN
  • MEMBER
  • 1996 PONTIAC GRAND PRIX
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 165,000 MILES
Why do have only 6 volts at tail lights
Do you
have the same problem?
Yes
No
Saturday, March 26th, 2011 AT 1:52 AM

7 Replies

Tiny
CARADIODOC
  • EXPERT
If you're measuring that when the bulbs are still plugged in, suspect a bad ground.
Was this
answer
helpful?
Yes
No
Saturday, March 26th, 2011 AT 2:03 AM
Tiny
HANDYMAN
  • MEMBER
Ware do I start looking?
Was this
answer
helpful?
Yes
No
Saturday, March 26th, 2011 AT 2:50 AM
Tiny
CARADIODOC
  • EXPERT
Are you measuring with the bulbs plugged in?
Was this
answer
helpful?
Yes
No
Saturday, March 26th, 2011 AT 3:12 AM
Tiny
MHPAUTOS
  • EXPERT
Pull the globe and test the power at the socket, what is the reading there? What condition is the battery?
Was this
answer
helpful?
Yes
No
Saturday, March 26th, 2011 AT 3:29 AM
Tiny
CARADIODOC
  • EXPERT
The problem is we don't know how this testing is being done. If the bulbs are removed, even if there is a bad ground, 12 volts will still be measured with a voltmeter or a test light. All it would take is a tiny carbon track in a corroded connection and a voltmeter will pick that up as 12 volts. In this case a cheaper test light would be more accurate and would show 0 volts. If the bulbs are in place and the test point happens to be the ground side, there will be between 4 to 6 volts there because current will find an alternate path to ground through the tail lights and a different socket's ground wire. That means the supply wire is okay. If 6 volts is found on the supply wire when only one bulb is removed, there could be a high resistance connection. The clue would be found when the other bulbs are removed or the signal switch is moved to either direction to isolate the brake light bulbs on both sides. There's just too many variables and possibilities to make a good guess on how to proceed. There will likely be a real easy fix, ... IF we know what they did to find that 6 volts.
Was this
answer
helpful?
Yes
No
Saturday, March 26th, 2011 AT 4:08 AM
Tiny
HANDYMAN
  • MEMBER
Okay let me give you a run down! Before I got started, I had no brake lights, turn lights or running lights in rear of car. I know the turn flasher is bad, I tested it with a ohm meter. Took out all bulbs checked out okay and are the correct ones. The flashes work only in front. These bulbs come on but only have 6 volts at plug with bulbs out with a grounded circuit tester. With key on I have 6 volts at the fuse box, 6 volts at brake light switch. The bulbs in the rear of the car will not even try to come on but have 6 volt power at plug with out bulbs. If this is helps when I put on the brakes the radio lights go off and when I turn the turn signals on the radio flashes. Thanks for all your help!
Was this
answer
helpful?
Yes
No
Saturday, March 26th, 2011 AT 1:44 PM
Tiny
CARADIODOC
  • EXPERT
Measure the battery voltage. You must have 12 volts all over. If the battery is bad that would explain all of the symptoms.
Was this
answer
helpful?
Yes
No
Saturday, March 26th, 2011 AT 7:29 PM

Please login or register to post a reply.

Recommended Guides