How do I find the low beam "positive" wire?

Hi,

I'm adding a DRL control module and harness to my '95 pickup to turn off my daytime running lights (too bright for night) when my low beam headlights are turned on. There is one wire I need to connect to the "Low Beam Positive" wire. The back of the headlight bulb has a 3 wire connector. How do I know which wire is the "Low Beam Positive" wire?

Thanks!!!!!!!!!!!!!

 

I would turn on the low beam lights. With a Volt Meter Ohm Meter (VOM) set on 12 volts and having leads on the VOM with needle like probes, press the red lead (positive ) on VOM into each of the three leads one at a time on the headlight plug with the black lead from VOM on the frame or ground. When you see 12 V you found the low beam positive wire.

If you have not used needle probes on a VOM they are very sharp and will puncture the insulation to the wire being tested. Only a small puncture is needed and it is some what of a pain to do but I have done this a number of times to find voltage. If you think you need to cover the puncture you can use electrical tape. But this is not normally needed

Alternate method - remove the headlight from housing ( or see if you can get at the three wire plug) and with it pluged into the three wire connector pull the connector back off the headlight prongs a little to expose the three prongs a little . Then read the voltage on each connector with the Low beams on. You can use regular VOM wire leads to do this.

 

Followed your advice and located the low beam positive wire...thanks!



The DRL's came with a wire harness and control module...one wire to the positive batt post, one to the negative, and the wires to the lamps. There was one extra wire that you splice into the low beam positive wire. When I start my truck now the DRL's come on and turn off when I turn off the engine. In the evening when I turn my headlamps on the DRL control module senses power to the headlights and shuts the DRL's off immediately. I used to live in Canada and DRL's have been mandatory on cars since 1995. I just like the added safety of being VISIBLE even on a sunny day. I installed 2 Cree LED 2x6 inch lamps and they are SOO BRIGHT there's no way I could have them on at night. I got the lamps, harness, and control module for less than $50 on Ebay...VERY pleased with the results!

 

Your welcome

 

which wire was it?

 

I want to make sure I don't "short-circuit" anyone's truck, so let me try to be very specific...my truck is a 2wd, extra-cab, 4cyl, auto trans, a/c, produced 10/94.

The headlamp plug has 3 red wires...one with a WHITE tracer stripe, one with a GREEN tracer, one with a YELLOW tracer. The red wire with the YELLOW tracer stripe is the low-beam positive wire.

Once again, the DRL harness made it SOO simple to wire up. The control module has 5 wires...one to the positive batt terminal, one to the negative terminal, two wires to the lamps, and the one to the low-beam positive wire. When I start my truck now the DRL's come on and turn off when I turn off the engine. In the evening when I turn my headlamps on the DRL control module senses power to the headlights and shuts the DRL's off immediately.