Headlight All On Mod

[RedBowTies88]

This is a write-up for how to make your low beams and/or fog lights stay on when you switch to high beams...This mod costs all of about $1 and should take no more then 15 minutes..its very very easy and use's the trucks own built in fusses and relays. Credit for this goes to Will from duramax diesels...i just made some additions and modifications..

All you need is a set of diodes that you can get from your local Radio Shack. The part number that I used was 1N4004. I have read that 4001,4002,4003 and 4004 will all work. These diodes come in a 2 pack and cost $.97.

You will do this mod under the hood at the fuse block on the drivers side of the truck. Make sure that the truck is off before reaching in there. You shouldn't need to unhook the batteries or anything like that.

On the bottom of the relays is the numbers for the different pins. You will be using the 85 pin for these mods. Also, on the bottom of the lid of the fuse block is a diagram showing the numbers of the pins along with which relay goes where. The 3 relays that are used are in the lower left hand corner of the fuse block

Hi-lows on at the same time.
You will need to connect the 85 pin of the low beams relay to the 85 pin on the hi beams relay. Make sure that the "bottle cap (or end with the stripe)" is going towards the hi beam relay. You can either wrap the wire around the metal pin or slide it into the hole that the pin goes into. Either will work.

Hi-fog on at the same time.
For some reason GM decided that when your high beams are on, your fog lights don't need to be(actually i believe this is a law) . Well I like my fog lights on adding more light. With the hi beams on adding a lot of light, then the fog lights on adding more light can't be a bad thing right?

To do this you will need to connect the 85 pin of the fog lights to the 85 pin of the hi beams. Make sure that the "bottle cap (or striped end)" is going towards the hi beam relay. Again you can either wrap the wire around the pin or push it into the hole that the pin goes into. If you are doing the lows plus the fogs it can be a little tight on the 85 pin of the hi beam pin. For this I wrapped one diode around the pin and the other got pushed into the hole with the pin(i pushed both into the slot...they fit you just need to push down hard on the relay) . You will still have control of your fog lights on low by switch but by doing this the fog lights will always be on with hi beams.

This Mod works perfectly with HID's as well as regular bulbs.

The pic shows how I have it wired. Sorry for the poor picture but hopefully the labels will help better explain things. the second pic is what the diode pack looks like from radioshack..its on the left