View Full Version : High Four Headlight Conversion.

12-14-04, 05:03 PM
Those who own chevy trucks, pre 93 Fleetwood's and, Escalade owners, should find this nice and useful.

What this does is turns your low beams back on when you switch over to your high beams to give added visibility.

This is extremely simple, and rather inexpensive. DO NOT be tempted to buy other peoples kits for 20 bucks. This requires a little experience and some tools.

You are going to need:
-30 Amp headlight fuse.
-Four relay crimp connectors.
-Two 3M style tap splice connectors
-Two Battery Size power connectors.
-Wire Crimper and stripper.
Other than 88-98 Chevy, know which wires go to low and High beam.

Ok, now for the process, it doesn't take more than a half hour if you prepare your relay and wires ahead of time.

-The two wires that will lead to your High and low beam should be approximetly one foot in length, and you should be placing your relay close to where you will be tapping into the headlight wires.
-Depending on how far away your battery is, cut your wires to according length, and make sure you leave some slack.
-A 30 amp fuse has a port for where your power inlet is, your ground, Your switch, and your main. 87 is your main power. 86 is your Switch in from the high beams. 85 is your relay ground, and 30 is where the low beams are plugged in.
-Use your 3M connectors and attach your 30 to the low beam, on a 88-98 chevy, it is a tan wire.
-Next, use your other connector to attach the 86 to your high beam wire, on an 88-98 chevy, it is a bright green wire. Your high beam is your "Switch" that will turn the low beams back on when you activate the high beams from the cabin.
Next remove your battery cables starting with your negative, then positive.
-Take your 87 wire, and place it on your positive terminal, and reattach your positive cable.
-Take your 85 wire and attach it to your negative. When you place this connector on your active terminal, the relay will begin to click until the connector is fully attached to the terminal. Don't panic, this is normal.

Start your vehicle and check your lights, then turn on your highbeams. If all four come on when you put the high beams on, you did it correctly.

11-29-05, 01:56 AM
I have done this mod many many years ago on my 91 Bonneville with great success. Do NOT be tempted to use diodes (semiconductor devices that allow power to only go one way) to do this. It is easier and faster to install, but will quickly overheat and possibly damage the factory wiring harness. The factory harness is borderline now with enough power to have the lights at 100% intensity, so this mod is a great way to significantly increase your light on the road.
My experience is the relays from Radio Shack last only around 2 years before they fail. Good sources for relays are VW's and Audi's in the junkyard often have this same relay in several places under the hood. You should be able to get them for very low cost, if not free (yes, legally, just ask, don't steal them, ok?)

This mod also works on the 93-96 Fleetwood Broughams.

12-07-05, 12:55 AM
I have been trying to figure out why on my 1989 Deville my low beams turn off when I select high beam. I guess the answer is: That is the way they are supposed to work.

12-08-05, 02:14 AM
I honestly think it started with trying to save some $$ on wiring and to reduce current drain when the lights are on. Current is more balanced with it going from a 55 to a 60 bulb instead of a 55w to a 60w and leave the 55w on. You may not think that it saves $ on wiring, but consider each and every car GM makes and save 12 feet of 16 gauge copper wire. It adds up in a hurry.