Cadillac Owners Forum banner

HID relay buzzing with capacitors after kit install

24K views 85 replies 6 participants last post by  Shooter2384 
#1 ·
Hey guys, I got the elite 9006 kit from the retrofit source installed in my 2013 ATS luxury. Even with an HD relay and a capacitor on each headlight the relay buzzes almost constantly. The right headlight where the relay is even shut off on me while driving last night. As soon as the light shut off the buzzing stopped. Then today I started my car and no buzzing until I let it sit for a little bit. Any thoughts on what it could be? This also got installed professionally at a shop who installs VVME kits so I highly doubt the workmanship is at fault.
 
#2 ·
Sounds to me like a bad relay, but may be a faulty capacitor not supplying smooth power. The buzzing is almost certainly from the relay. I would contact TRS and see what they can do to make it right. The only other thing I would consider is the connection between the battery (or distro post) and the relay. The lights shutting off is a result of the cars computer not being happy with the power draw from the lights and consequently shutting down the curcuit.
 
#4 ·
TRS seems pretty stumped, they want me to tear it apart and test all the stuff but I don't have the tools to do so. I do know the capacitor on the problem side is a VVME one and the other is one from TRS. I would think it wouldn't matter as they are the same connections. I unfortunately do not have pictures but I have a hard time believing they messed it up during the install, though anything is possible. Does anyone know how to disable the DRL's? Is it as easy as pulling a fuse? If the DRL's don't light up fine, I just want to be able to leave my lights on auto. I've heard nothing but positives about the Morimoto kits so I'm not sure if switching kits would help. If the computer isn't happy with the power draw, why wouldn't it kill both lights? Also, TRS told me only one capacitor was necessary but the same thing was happening whether there was one or two in place.
 
#5 ·
Ok, so from what I can see without getting that plastic cover off, the red circled part is the HD relay... I think. The red plug is the positive, and nothing attached from what I can see popping the red cover off. Is the positive supposed to be the distro post? I can try and get more pics this weekend of the install when I am in a garage. Red Bumper Auto part Automotive exterior Technology
 
#11 ·
Without a capacitor I would expect the relays to buzz during DRL operation only, because of the PWM voltage.

There should be no buzzing during normal headlight operation because of the constant 12V.

The capacitor is used to level out the PWM of the DRL, and should be installed across the relay's coil.

Keep in mind the ballasts do make noise as they regulate the current to the HID bulb. Louder at startup and quickly quieting down, but still recognizable.
 
#12 ·
I understand that. But it is definitely the relay. As I said, I could feel it vibrating and hear it at the shop before he put the bumper back on. If it's not secured properly could that cause the buzz and the computer shutting the light off? If it buzzes during DRL operation, fine. I just don't want to be driving around with one headlight constantly out and I don't want to have to use the stick to disable auto everytime I drive in the day. That's why I got the capacitors.
 
#14 ·
I can't actually get to it without tearing my bumper off, which makes me kind of nervous. Here are two better views of where the relay is attached to the battery post thing. Since our actual battery is in the trunk Cadillac put this up front for access. Here are two better views with the relay circled in red. The tall metal post on the left is the positive. Auto part Engine Vehicle Car
Auto part Vehicle Engine Electrical wiring Bumper
 
#15 ·
I can't actually get to it without tearing my bumper off, which makes me kind of nervous. I'm going to try this weekend. Here are two better views of where the relay is attached to the battery post thing. Since our actual battery is in the trunk Cadillac put this up front for access. Here are two better views with the relay circled in red. The tall metal post on the left is the positive. View attachment 195530 View attachment 195538
 
#17 ·
I wonder if he put the capacitors between the ballast inputs and the relay output. But if that's the case wouldn't the lights not work at all? I've heard of other people using two capacitors as well. Did the relay look in the right place to you as per my pictures?
 
#18 ·
I don't see a relay in that picture. You circled the 12v input to the relay harness. Follow this wire down to the relays.

I am suspecting the capacitors are installed as you just explained. I would guess that the people using 2 capacitors are not using a relay harness. In that case the capacitors are installed between the cars output and the ballast input, one on each side.
 
#20 ·
Yes, you wouldn't be getting any lights if that was incorrect.

The capacitors will have no affect if they are installed at the ballast inputs, as i now suspect they are.

With that said, during DRL operation, I would expect to hear the relays buzzing, but not buzzing when the headlights are turned on.
 
#21 ·
Ok. I'll give the shop a call today to see if he remembers where he put them. If he did that I'm tempted to try and fix it myself. My only question I guess is looking at the diagram, the input from car on the relay. I understand the capacitor plugs into that, but then where does the other end of the capacitor plug into on the vehicle?
 
#24 ·
ok i lied a little bit. the vehicle headlight connector is inside the headlamp assembly and connects to the HID bulb on the inside part of the seal, to get the input power out of the assembly so you can use it. here is a pic to explain:


the connector next to the bulb is where the factory connector will plug into. the rubber grommet at the bottom of the pic is what you will see at the round headlight cover, everything to the left of it is inside the headlight assy.

the connector on the right is now the power to the ballast, but since youre using a relay harness, it is going to power the relay. this is where you want to install the capacitor.

the other two connectors are power to the bulb from the ballast and are different. you dont need to touch them as they are correct the way they are.

find where the capacitors are installed, remove them, and connect the remaining wires (the ones that were on each end of the capacitor) back together. one end should lead back to the relays, and the other end should be to an HID ballast.
 
#25 ·
That made no sense to me as the diagram shows just one input from the car. Base on what you wrote it sounds to me the capacitors are where they should be, between the ballast and the relay. If each bulb has that connector how the heck do I do it with one capacitor? I'm sorry, I just don't get it.
 
#26 ·


ok lets look at this again.

INPUT FROM CAR - This is the trigger to turn on the lights. whether it be DRL or headlights. just needs a +12V to tell the relay in the harness to switch on and send power from the 12V battery connection to the output of the harness. when the relay gets this constant 12V, it is on and you HIDs come on. we want to use the factory headlight connector as our trigger.

now since DRL operates as a PWM and is not a constant 12V, we want a capacitor here to smooth out that PWM as much as we can. A PWM signal will tell that relay to click on and off as fast as that PWM signal changes, causing the relay to buzz.

The relay harness takes care of power to the ballasts. thats why its connected to the battery. its just acting as a remote switch (turned on and off by the INPUT FROM CAR) between the battery and the ballast.

just one of the factory headlight connectors is all that is needed because it is only being used as a trigger to turn on that relay. And the capacitor needs to go between the factory connector and the relay harness input to smooth out that DRL signal driving the relay to turn on.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top