Hid Lights Question

emwolb469 · August 5, 2009

Hi everyone,

I wanted to get some nice HID lights for my 07 sierra and was wondering if it will effect my daytime runners? the reason I ask is when I installed HID's on my other vehicle, I had to disconnect my daytime runners because when they would come on, the lights would flash like a strobe light (Yeah sounds crazy but they did). I dont want to disconnect my daytime lights in the Sierra. Has anyone done this? Anyone have any trouble? Thanks!!

C. Charles Hahn · August 5, 2009

Yes, you will have to pull the DRL fuses to run HIDs on your truck. I just installed a set of HIDs on my 08 Sierra and the DRL function does not feed proper voltage to the ballasts -- it's not good on them to run on partial voltage, obviously.

emwolb469 · August 5, 2009

Yes, you will have to pull the DRL fuses to run HIDs on your truck. I just installed a set of HIDs on my 08 Sierra and the DRL function does not feed proper voltage to the ballasts -- it's not good on them to run on partial voltage, obviously.

Thanks a lot. I Appreciate it.

Spurshot · August 5, 2009

Charlie,

If you put a relay in the system at the bulb connector, wouldn't you then be able to reinstall the DRL fuse, reactivating the DRLs? (as long as the DRL voltage was up to throwing the relay)

C. Charles Hahn · August 6, 2009

Charlie,
If you put a relay in the system at the bulb connector, wouldn't you then be able to reinstall the DRL fuse, reactivating the DRLs? (as long as the DRL voltage was up to throwing the relay)

Hmm..... I hadn't thought about that, but you're probably right. Guess I'll have to play with the relay once I get it hooked up tomorrow and see if the DRL signal will activate it. I stand corrected!

sierrawhite160 · August 7, 2009

i pulled the drl fuse once i installed my 6000k hids. i did so bc it seemed this was the norm, in order to prolong the life of my new bulbs, not running them constantly at a diff wattage.

does anyone know the output of the bulbs while in drl only mode? will my relay step down/up the wattage to a constant 35w regardless of input?

Spurshot · August 7, 2009

Jeff,

If you put a relay in the system, the purpose was to supply power from another source other than that provided in the OEM harness. You likely did this to limit the amount of electrical load on the OEM harness, to provide some protection that it will not fry the harness. In a relay type circuit, the OEM harness/circuit is just used to provide a signal and enough current to trip the relay. The relay is just a switch that allows you to use a larger circuit to acutally power the lights.

So, if the relay will properly function at the lower current of the DRL signal, the power circuit will be connected and it will provide full power of whatever it's capacity is.

I probably haven't explained this well. But suffice to say, a relay is just a switch that is often used to allow a small capacity circuit to control a larger capacity circuit.

C. Charles Hahn · August 7, 2009

Jeff,
If you put a relay in the system, the purpose was to supply power from another source other than that provided in the OEM harness. You likely did this to limit the amount of electrical load on the OEM harness, to provide some protection that it will not fry the harness. In a relay type circuit, the OEM harness/circuit is just used to provide a signal and enough current to trip the relay. The relay is just a switch that allows you to use a larger circuit to acutally power the lights.

So, if the relay will properly function at the lower current of the DRL signal, the power circuit will be connected and it will provide full power of whatever it's capacity is.

I probably haven't explained this well. But suffice to say, a relay is just a switch that is often used to allow a small capacity circuit to control a larger capacity circuit.

That's basically the idea, yeah. And I can confirm that yes, the supplied 70% voltage @ DRL load WILL trip an HID relay, supplying the ballast with full power directly from a fused link to the battery. I hooked mine up this way today and tested the DRLs, which seem to be working just fine. Next I'm going to see if I can rig up a harness to run my fog lights from a relay as well. The only slight problem here will be the unavailability of 5202 harness connectors in the aftermarket.

Also, to the poster that mentioned lower voltage would hurt HID bulbs, that's not entirely true. The ballasts are actually the part you need to worry about. They'd blow long before the bulbs would.

Spurshot · August 7, 2009

Charlie,

That's great news about the DRL circuit being able to run the relay. What kind of relay are you using? I'm definitely going with the relay setup on the 99's Lo beams. I want the DRL function as I feel this is an important safety aid.

C. Charles Hahn · August 7, 2009

Charlie,
That's great news about the DRL circuit being able to run the relay. What kind of relay are you using? I'm definitely going with the relay setup on the 99's Lo beams. I want the DRL function as I feel this is an important safety aid.

Whatever the relay is on the harness Spencer sent with my low beam kit is what I'm running.... I don't know what brand or anything else about it. It just says "HID" on the top and has the diagram of the relay pinout on the top of it.

Spurshot · August 7, 2009

So, is it two separate relays or one? If it's just one, I would think you just use one light connector to power the relay and have two positive polarity leads coming out of the relay, one for each side?

Any marking on the relay with regard to current rating?

C. Charles Hahn · August 7, 2009

So, is it two separate relays or one? If it's just one, I would think you just use one light connector to power the relay and have two positive polarity leads coming out of the relay, one for each side?
Any marking on the relay with regard to current rating?

Just one relay, yeah. It's a 40A relay, but the positive connection to the battery has a 25A fuse on it (between the battery and relay).

I found a site with what appears to be the exact same harness I have:

http://www.carhidkits.com/xenon-hid-kit-99...arness-200.html

You could probably put something like this together yourself for less using AutoZone parts, which I think I'm going to be doing for use with my fogs.

MS3DALE · August 7, 2009

Next I'm going to see if I can rig up a harness to run my fog lights from a relay as well. The only slight problem here will be the unavailability of 5202 harness connectors in the aftermarket.

This is the issue I've run into as well,I want to do the same thing,Run my fog lights from a relay,and I can't find any 5202 connector/relay kits

ffthornton · August 7, 2009

I am just making a suggest, But could you use one side of your low beam head lights (using a relay) to supply power for the HID low beams. Then use the other plug to turn on another relay for your fogs. Then you will have low beam and fogs on the same time without pushing a button to turn them on. I dont konw if it will work.

C. Charles Hahn · August 7, 2009

I am just making a suggest, But could you use one side of your low beam head lights (using a relay) to supply power for the HID low beams. Then use the other plug to turn on another relay for your fogs. Then you will have low beam and fogs on the same time without pushing a button to turn them on. I dont konw if it will work.

It would certainly power on the fogs, but with the way you're describing setting it up, you wouldn't be able to manually turn off the fogs, nor would the indicator light on the dash tell you the fogs are on.

The point of the relay is only to bypass using the factory wiring harnesses for powering the HID ballasts... it has nothing to do with making the fogs turn on automatically along with the low beams (though I'm sure that could be done with a little creative -- albeit more difficult -- wiring) in this instance.