So basically i got myself a set of NHK projectors and retrofitted them into the autosaver 88 single piece headlights [non sport]. tested the plugs before i started building the harness. so after testing the pins i got : Low beam; pin1 12v pin 2 grnd, pin 3 inactive Hi beam; pin 1 ground, pin 2 inactive, pin 3 12v also noted that pin 1 is +12v even when headlights are off. So i built the harness and in the meantime something happened and now pin 3 is always hot. im over 12 hours into building the harness and this ****ery happens. im assuming a bad dimmer switch? the hi beam indicator still works which throws me off. pin 1 still acts normal switching from hot to ground when switching from lo to hi beam but pin 3 stays hot even with the truck off now. pin 1 is normally hot when truck is off but that should be the only pin hot when off.

My harness is wired like this; pin 1 goes to relay coil, pin 2 and 3 go to the other end of the relay coil. in theory when low beam is active pin 1 will give hot and pin 2 will give ground to activate coil, in hi beam pin 1 is ground and pin 3 provides 12v to coil. this allows the relay to activate during high and lo beam to keep the projector powered. the projector hi beam solenoid is wired to pin 1 and 3 directly and only activates during high beam. since pin 2 and 3 completely disconnect from circuit during lo and hi beam operation [no continuity] i decided not to use schottky diodes for reverse current protection. i do have them if i need them but i dont think so since there isnt continuity between the pins 2 and 3 when low or hi beam is active. the harness isnt plugged into anything now and i currently have no headlights so please help with any advice.
thanks in advance,
Jacob

 

From the factory, the headlight switch pulls way too much current to have a long life. To alleviate this issue permanently, most folks setup relayed headlight harnesses to allow the headlights to pull current from the battery and use the headlight switch as a switching mechanism only. For more information, you can speak with these folks that provide a relayed headlight harness for 2nd gen trucks with sport headlights (4 bulb) - https://ceautoelectricsupply.com/hea...ion-relay-kit/

You can also check out this relayed headlight harness for non-sport headlights - https://www.genosgarage.com/product/...ories-lighting

 

im not sure you understood my question. WHY is my high beam pin 3 at the headlight socket staying hot constantly now? It should only become hot when the brights are applied. pin 1 still acts as it should and switches from hot to ground when brights applied. pin 3 is my problem pin and i believe it runs from the dimmer switch which is the stalk that controls your brights.

 

Also as i noted above i have the ability to build my own relayed harness with hq DT plugs and 12 gauge wire. im just lost on what could be causing the pin 3 issue of the stock 9004 plug

 

What year is the truck ? There are significant differences between trucks with the round pull style headlight switch and the later "chicken head" three position switch. From your description I'm guessing it's a 99+ truck.

 

What kind of relay are you using? Normal Bosch-type, which has connectors marked 30, 85, 86, 87 (and possibly 87a)?

 

Sorry. Due to late night reading, I missed your inference of using a relay in your custom harness.

 

What NHK projectors are you using? Keep in mind HID's don't have separate "bulbs" for high/low. They use one bulb and there is a shutter inside the housing that moves to provide the light pattern to raise up a bit. You need to use relays to provide power at low/high. Supply power to the relays from the battery and use the headlight switch for powering the relays(high/low). You will also need to wire up the shutter to the high relay so it will raise the beam pattern. Are these what you are using? Read the note:
Wiring: Please note that these units come with 4 bare wire leads. One power and ground for each of the low and high beam inputs. We offer pre-attached 9006 and 9005 inputs for easier hook up. Single filament applications can use a direct connection to factory low beam plug with a high beam splitter. Dual filament applications will require a MotoControl wiring harness to make this unit plug and play.

 

it is a 2001 2500 CTD

 

Yes standard double pole relay. 85 ans 86 are coil pins 30 and 87 are common and hot. please note the probelm is with the harness removed.