Thread: head light issue

ok...i just installed 91 headlights on my 93 classic. to do this i had to splice in a 9004 headlight bulb connector. i used one of those parts store connectors with the larger wires for use with higher wattage bulbs. after finally figuring out what wire colors are what on the harness side using a test light i started to twist the wires together to figure out what colors were what on the new connector (high beam, low beam, ground) got it all working and soldered together and shrink tubed up.

i installed the brand new silver start ultras and turned the lights on......they seemed dim. not they are ok to drive with but not nearly as bright as the ultras were in my 93 headlights. i also noticed with my low beams on my "high beam warning light" on my dash glows a little. is it possible these "high load" connectors do not have enough resistance are are causing some craziness?

wires might been wrong

I don't think so. It seems more like you would be limited by the smaller OEM wire diameters (and so not able to take advantage of the large connector wires). Is the harness wiring the same otherwise for 91 as the 93? (aside from the connector)

the wire in the middle of a 2009 connector is ground. that is soldered to the solid black wire on the harness side.....the solid black did not get any power in high or low so i am 100% positive that is the ground (not to mention it was a smaller wire) the other two wires on my connectors are correctly installed as well because if i flipped them the high beam would come on when it was in the low beam position.

short story, i know for a fact the wires are correct.

but i had silver star ultras in my 93 headlights before i swapped them out and they were PERFECT. only thing that has changed is the bulb number and connector.

Hmm that is pretty weird. What I meant was, do both bulb models use the same amperage from the car's harness or not? (IE, are the different bulb models compatible with the car's wiring aside from the connector type). I don't really know how the lights are wired up in the car, I was just sorta speculating on what could be causing the dimness.

im not sure but the wattage is the same so i would assume the amperage would also be the same. im going to go to drop by work tomorrow and use my volt meter to check the volts and make sure im getting full power. i did notice the wire seems a bit corroded that i was soldering (by corroded i meen a little tarnished) but no more than normal.

I don't think the FSM distinquishes between 91 and 93, so I guess it should be the same. Even the actual wiring at the bulbs for the ones with daytime lighting is the same as those without. Here's the FSM diagram, I just took a second to highlight the wires so you can double check while you're out there. It looks pretty straightforward so I think if they work now they're probably right. Other than correct wiring, I think your only problems would be the connections or something. I don't see what else could cause it

Also, as far as the dimly light high beam indicator: the bulb in the meter is powered by the left side high beam wire according to the diagram, so it could only be on if there was power in that wire. I would just double check all your wiring and connections to be sure it's all good.

Anyays, what I see in this diagram is this for the wiring at the bulbs from the harness:

B - Ground
R/Y - Low Beam LH
R/B - High Beam LH
R/L - Low Beam RH
R/G - High Beam RH

Good luck!

what i am going to do soon is check the voltage before the harness and before the solder. then i am going to make sure the ground reads the same after the solder. what i think is happening is the bulb its self is getting 12v. but since such a large wire (12gauge) is soldered to a very small wire (16 or 18gauge) i have some voltage backing up and causing aquward things to happen like making the high beam light glow.


if i can confirm this is the issue i will add another ground to the new harness and see if that helps.