A loud humming sound is coming through my radio whenever the parking lights are on. The sound level doesn't increase when I accelerate, so I do not suspect it is my alternator. I'm not very electrically literate, but do know how to work a digital multimeter.

My setup is a Pioneer deck, a Soundstream amp, in a 3rd gen 4runner. The grounding for both the deck and amp have been checked.

Could this be an electrical leak from the parking lights? How can I check for this?

Thanks!

 

Is the sound present when the engine is off? Did you check the battery ground itself? And when was the sound introduced, did you recently add something to your setup?

 

Where did you ground your lights? I'm almost positive it's a grounding issue. Check your grounds again and make sure that all paint or corrosion on the surface has been cleaned off. Sometimes even the amp can make that sound. Some amps allow a lot of interference even if they are well grounded. Keep us posted.

 

what do you mean by the sound coming through your radio? If it's coming through your speakers, your speaker grounds need to be checked. My friends' speakers hiss as his engine revs, sounds like he has a turbo. Check light wiring first, then speaker grounds.

 

The sound occurs even when the engine is off.

This started about 6 months ago (no mods around that time or after), system was installed almost a year ago. The noise has it's good days and bad days.

I'm pretty sure it's not the amp's ground, but i'll DMM that ground again. I scraped off the paint before and made sure there was solid contact.

From what you guys are saying, sounds like I starting with the lights' grounding.

Would this be in the engine compartment or towards the steering column?

Thanks again!

 

Well if it's not humming when you accelerate, then you are somehow getting an electrical interferance with the lights. I would relocate your ground to the amp and see if that helps. Where on the vehicle are your grounds located?

 

I wanted to post, in case someone else has this same problem and needed a solution.

The fix was to run a new ground for the deck. The lines for the dimmer and ground were wrapped together heading into the deck. I tapped the ground off before the cables bundled, so I had the ground completely isolated from the dimmer cable. That did the trick.

Thanks for your help, guys!