I have luminics titanium white bulbs, and with people having problems with harnesses burning out I decided to test the watts that the bulbs draw.

First we tested the volts that the alternator was putting out, and nothing surprising there as it was putting out 13.5 volts. Next we tested how many amps that the headlight was drawing.

With the low beams on we got two different readings depending on which connection on the harness we tested. The left prong was reading 3.5 amps (which is 47.25watts), and the right prong was reading 8.5 amps (114.75watts)! Can anyone clarify why the two different readings, and the huge difference between the two? First we thought the higher reading could of been the high beam power, but that can't be right since the high beams were not on.

Hope someone can explain!

 

no one can shed somne light on this???

 

humps to the BUMP

 

reading current incorrectly? you have to have the meter in series with the circuit to measure amperage.

 

Yep, the meter was in series

 

hmmm.... .. weird.... the only thing is....what's with the two connections...

to wire it in series.. you actually need to break the circuit... and wire it up to the prong or wire that provides the power to the bulb and stick the meter in between.... there shouldn't be another prong involved....

 

I'll try to explain how it was done without pics:

If you're looking at the harness, there are three female end connectors in a semi triangle shape. The "point of the triangle" being at the bottom. we broke off 3 little pieces of a paperclips and stuck them in each female end so there would be something to work with. Next, grabbed 2 seperate wires with alligator clips on both sides. Attached one side of the clip to the paperclip piece that was sticking out of the harness's bottom "point" connector, and attached the other side of the alligator clip to the bottom "male" end of the conector on the headlight bulb. Then did the same thing with the left side of the harness (alligator clip on female end to clip on the male end) So with power running through two of the connectors it was time to put the meter in the series. The black cord on the meter was switched to be the common, and we touched it to the bottom "point" prong on the headlight bulb. The red cord was connected to the female right side prong (that had no alligator clip running from female (harness) to male (headlight bulb)), and it gave the reading I posted.

Just for the hell of it we switched sides with the clips and metered. Put the alligator clips running female to male ends on the right side (harness to bulb), and put the red (+) meter cord on the left female end. keeping the black meter cord as the common on the bottom connector of the headlight bulb. Giving a totally different meter reading than the previous attempt.

The circuit should of been broken, and the meter placed inbetween by wiring it up this way.

Sound right to you?

Any suggestions?

 

The BEST way to measure the current drawn by the headlight circuit is to measure across the fuseholder - either with the fuse removed, or sometimes easier, across a blown fuse.

Here's the circuit:



Tomas