The Machine

Hey guys,

I've got 1 relay in my homemade relay block that buzzes briefly upon startup and power off and I'm wondering why.
I have a wire tapped into my dome light circuit that is the signal wire for this particular relay, the power and ground wires should be fine because the other relays I've daisychained together run smooth, but for some reason when I open the door to power the circuit or the dome light goes off after ignition, it buzzes for a brief second. Any thoughts??

feifel

iTrader: (3)

is it a new relay? if so if the control voltage isn't enough for the relay they will buzz other than that it could be a bad relay

rymax101

I had this problem in my jeep. what caused it in that was the voltage came out of the computer and wasn't constant. It was 12vdc but had some pulse to it. You cant see it in the bulbs, but when I hooked up a relay to it, they sounded like they were buzzing. I dunno if this is the same just sharing my experience with relays that buzz.

The Machine

Sounds like your correct. After a ton of reading it looks like the dome light circuit uses PWM or pulse width modulation. A very fast on off sequence of delivering power to achieve the dimming effect, this on off sequence turns the relay off and on quickly, which in turn is the buzz. I've read you can add capacitors and resistors to the circuit but that sounds like a lot of hassle. Did you ever come up with a solution for your buzz? I am hoping there is another wire on the same circuit without the pwm, idk.