QuestionProblem: indicator bulb blew so replaced with 12v 21watt as per usual, but when turned on to test, it smoked inside and the glass went for clear to white in about 3 or so seconds. Basically fried itself. battery read 12.74v and the contacts are clean. dud new bulb ? maybe ?? any idaes thanks
AnswerHello James,
This is a question i get asked very frequently, i recommend reading the answers i have given on light in the past, however, for the current moment:
This sounds to be a situation where you have one of three things going on.
1. Bad Ground wire
2. Short in the wire
3. Ground out
To start, if the vehicle has a bulb system where the bulb is dual filament meaning it handles say brake light and turn signal light, then you are dealing with a 3 wire bulb setup.
To check for a problem you will need a test light. Ground the test light and then probe the tip into the wires on the lights harness. One wire will make the bulb in the test light come on when the brake is pushed, the test light bulb should remain on as long as the brake is being pressed.
The next wire should turn on when the signal is turned on and the bulb in the test light will flash in time with the light.
The third wire should not make the test light turn on at all, this is your ground wire.
If the bulb to the test light blows, you know that that wire is where your problem is. Trace the wire and check for broken, frayed or grounded wires. If the bulb wont light at all, ensure it is not the ground wire, by testing the other wires, normally the ground wire is a solid color wire, however they can be multicolored. If the bulb is not lighting on a wire that it should be, then you know that that wire is part of your problem. Check that for broken, frayed, or grounded wiring, and also check all fuses controlling the light.
For additional information refer to my earlier post at this link on all experts.
http://en.allexperts.com/q/Auto-Electronics-3977/2010/11/Tail-Lights.htm
Please keep me informed of your progress.
Thank you and Good Luck.
