Why you should use relay harnesses with HIDs

ethlar

ethlar

Grumpy Moderator
Super Mod
5,477
4,308
Philly
Vehicle Model
Polestar 2
Body Style
Sedan
http://theeshadow.com/files/volvo/hidcomp.html

The author tested a few ballasts under warm and cold start conditions, just to show the amperage spike that happens when you first turn them on. Though he notes that the spike is too short in duration to blow a standard fuse, you are still pushing far more power through the wires than intended and it can cause a repeated fatigue situation where eventually you will develop issues with the stock wiring.

TrialColdWarm
Halogen Cold ~4.52a average (15a peek < 20ms) Warm ~4.52a average (14.25a peek < 13ms)
Osram H11 55w
hidtest02.jpg
hidtest13.jpg


Control Cold ~6.63a average (20a peek < 15ms) Warm ~3.38a average (14.73a peek, < 30ms)
Xentec 35w
hidtest03.jpg
hidtest05.jpg


HID50 Cold ~5.1a average (10.91a peek < 25 ms) Warm ~4.09a average (14.73a peek < 20ms)
50W Slim
hidtest07.jpg
hidtest11.jpg

DDM Cold ~4.36a average (13.64a peek, < 20ms) Warm ~3.95a average (14.93a peek < 20ms)
55W slim
hidtest15.jpg
hidtest19.jpg
 
Last edited:
It's an extremely cheap insurance policy to your stock wiring.
 
Good info. The only time I had aftermarket HIDs on a car they came with the relay harness. I had no idea what it was for, but I used it anyway. Thanks for posting the explanation.
 
Last edited:
fog hid kits are no different than low/high beam hid kits. I'd buy one.
 
Great info............ That's why I wish ppl/suppliers would give the complete list of what's needed with a product.
 
Dang anyone have a link to where I can order those? If DDM ships from China, I need to order some that ship closer so they arrive at the same time.
 
These are the same thing as relay harnesses? Forgive me, I'm a complete HID noob

EDIT: Nevermind, didn't realize I could scroll down. Found the relay harnesses for 11.99 each.. that means I need two, huh?
 
Last edited:
Ah, roger. Ordering now

EDIT

From an 8th gen thread:

"Here is what get hooked up to what:

1. Connect to Left Ballast input

2. Connect to Right Ballast input
NOTE: 1 & 2 may be reversed depending on where your battery is and how long the connector cable legs are.

3. Connect to the Positive + side of your battery.

4. Connect to the Negative - side of your battery or to any convenient chassis grounding point. There is no difference between connecting the ground line to the battery or the chassis. Electrically, they are exactly the same.

5. Connect to your car's stock headlight power cable.
Note: This connection can be to either the right or left headlight power connector. The other headlight connector is no longer used and should be covered in electrical tape or other material to protect the connector ends from the environment.

How it works:
The stock headlight power connector (5) powers the relay (6) which provides power directly from the battery (3 & 4) through a fuse (7) to the HID ballasts (1 & 2).

Got it?

Keep in mind that a Relay Harness is only necessary if your HID retrofit kit is a 50 Watt or higher kit.

A Relay Harness is NOT necessary for 35 Watt kits."

I'll assume he is incorrect about the 35W comment lol
 
Last edited:
ericc191 said:
Ah, roger. Ordering now

EDIT

From an 8th gen thread:

"Here is what get hooked up to what:

1. Connect to Left Ballast input

2. Connect to Right Ballast input
NOTE: 1 & 2 may be reversed depending on where your battery is and how long the connector cable legs are.

3. Connect to the Positive + side of your battery.

4. Connect to the Negative - side of your battery or to any convenient chassis grounding point. There is no difference between connecting the ground line to the battery or the chassis. Electrically, they are exactly the same.

5. Connect to your car's stock headlight power cable.
Note: This connection can be to either the right or left headlight power connector. The other headlight connector is no longer used and should be covered in electrical tape or other material to protect the connector ends from the environment.

How it works:
The stock headlight power connector (5) powers the relay (6) which provides power directly from the battery (3 & 4) through a fuse (7) to the HID ballasts (1 & 2).

Got it?

Keep in mind that a Relay Harness is only necessary if your HID retrofit kit is a 50 Watt or higher kit.

A Relay Harness is NOT necessary for 35 Watt kits."

I'll assume he is incorrect about the 35W comment lol
Click to expand...


thank you for the infor very helpful! :1: :thumbsup:
 
ericc191 said:
Ah, roger. Ordering now

EDIT

From an 8th gen thread:

"Here is what get hooked up to what:

1. Connect to Left Ballast input

2. Connect to Right Ballast input
NOTE: 1 & 2 may be reversed depending on where your battery is and how long the connector cable legs are.

3. Connect to the Positive + side of your battery.

4. Connect to the Negative - side of your battery or to any convenient chassis grounding point. There is no difference between connecting the ground line to the battery or the chassis. Electrically, they are exactly the same.

5. Connect to your car's stock headlight power cable.
Note: This connection can be to either the right or left headlight power connector. The other headlight connector is no longer used and should be covered in electrical tape or other material to protect the connector ends from the environment.

How it works:
The stock headlight power connector (5) powers the relay (6) which provides power directly from the battery (3 & 4) through a fuse (7) to the HID ballasts (1 & 2).

Got it?

Keep in mind that a Relay Harness is only necessary if your HID retrofit kit is a 50 Watt or higher kit.

A Relay Harness is NOT necessary for 35 Watt kits."

I'll assume he is incorrect about the 35W comment lol
Click to expand...

This is an old thread, but is this the same harness for a retrofit?
 
VNPP said:
This is an old thread, but is this the same harness for a retrofit?
Click to expand...
whenever you're using HIDs, whether it be a retrofit or new headlights, it's always better to get a relay harness.
so to answer your question, yes
 
ericc191 said:
Ah, roger. Ordering now

EDIT

From an 8th gen thread:

"Here is what get hooked up to what:

1. Connect to Left Ballast input

2. Connect to Right Ballast input
NOTE: 1 & 2 may be reversed depending on where your battery is and how long the connector cable legs are.

3. Connect to the Positive + side of your battery.

4. Connect to the Negative - side of your battery or to any convenient chassis grounding point. There is no difference between connecting the ground line to the battery or the chassis. Electrically, they are exactly the same.

5. Connect to your car's stock headlight power cable.
Note: This connection can be to either the right or left headlight power connector. The other headlight connector is no longer used and should be covered in electrical tape or other material to protect the connector ends from the environment.

How it works:
The stock headlight power connector (5) powers the relay (6) which provides power directly from the battery (3 & 4) through a fuse (7) to the HID ballasts (1 & 2).

Got it?

Keep in mind that a Relay Harness is only necessary if your HID retrofit kit is a 50 Watt or higher kit.

A Relay Harness is NOT necessary for 35 Watt kits."

I'll assume he is incorrect about the 35W comment lol
Click to expand...


What about the light bulb where is the plug for light bulb I see #5 is for car light plug but where is plug for the bulb??
 
red13devil said:
What about the light bulb where is the plug for light bulb I see #5 is for car light plug but where is plug for the bulb??
Click to expand...
#1 or #2 goes to power the ballast. Off the hid ballast, there will be a bulb connection
 
red13devil said:
It won't work on the ballast I had then. This well had to be order with the same ballast kit to be able to work.
Click to expand...
pic of your ballast?

Generic pic of HID ballast below. The red plug is what goes into the hid wire harness, and then the black line has the connection for the bulb.

rkqvvd7.jpg
 
webby said:
pic of your ballast?

Generic pic of HID ballast below. The red plug is what goes into the hid wire harness, and then the black line has the connection for the bulb.

rkqvvd7.jpg
[/quote
Click to expand...


Makes more sense now but my is 35w and why it only blown the driver side. R these fuse harness well help if it for sure them I'm order it in the morning.
 
things arent built identically, i had the same setup since 06, and this summer the drivers side started acting up but passenger side was fine
 
You must log in or register to reply here.
Back
Top