Grounding amp to roof of trunk

**thejavabuddha** · 09-03-2009, 02:30 PM

I have a MKV/A5 2005 Jetta. I am hooking up MTX Thunder564 4-channel car amplifier 70 watts RMS per channel. My question is, can I ground this to the metal roof of the trunk? Is that considered the chassis? There are lots of nice holes there that I can put a bolt and some washers after scraping off some paint and I would not have to drill any holes in my trunk. If I HAVE to I can take out the back seats and ground it to the seatbelt bolt but seems like a lot of work.

Thanks,
Bill

**soundman98** · 09-03-2009, 03:41 PM

it would be best to ground it to a solid point like a seatbelt bolt. or at least the chasis. there is just to much high resistance stuff between the trunk and the battery(like rubber bushings for smooth trunk operation), and could keep the amp from even working.

just remember-- a solid installation will rarely need to be touched again for service, unless you need to upgrade parts. it might be more of a hassle now to ground at the seat bolt, but it could very likely keep you from tearing your car apart every weekend when your amp starts acting wierd form a bad ground.

**DarquePervert** · 09-03-2009, 03:41 PM

That might work, but I wouldn't recommend it. I also wouldn't expect it to be reliable.
And no, the trunk lid is not considered part of the chassis.

**thewizard** · 09-03-2009, 04:00 PM

As everybody has already mentioned you are better off running your ground to a sound location such as a seat or seat belt bolt, this will help to avoid the possibility of overheating your new amp and listening to electrical whine instead of music.

**BIGGKATT01** · 09-03-2009, 04:11 PM

**thejavabuddha** · 09-03-2009, 07:52 PM

Originally Posted by DarquePervert

That might work, but I wouldn't recommend it. I also wouldn't expect it to be reliable.
And no, the trunk lid is not considered part of the chassis.

No, not the trunk lid, the ROOF of the trunk, under the rear window. Where speakers would go if there were any back there. It is solid metal and looks to be just part of the frame, or at least welded to it.

**brianhj** · 09-03-2009, 09:24 PM

Originally Posted by thejavabuddha

No, not the trunk lid, the ROOF of the trunk, under the rear window. Where speakers would go if there were any back there. It is solid metal and looks to be just part of the frame, or at least welded to it.

that's called the rear deck. i'd use a seat belt bolt.

**soundman98** · 09-04-2009, 09:37 AM

no, i would still mount it to a solid point like a seat bolt, or another structural piece-- the rear deck is not vey often built with electrical loads in mind

like i said, spend a extra hour or two on it now, and save yourself a days work later, do it the right way(you going to have to pull panels off to install the amp anyways)...

**thejavabuddha** · 09-04-2009, 05:35 PM

Alright, fine! lol.

I guess my next search will be "how to remove back seats 2005 jetta"

**boelle** · 09-05-2009, 03:41 AM

i would use the rear deck / roof.... but only if it is welded to the chassis... one way to make sure is to messure ohms.. one lead of the ohm-meter to a spot just nex to the rear deck and then messure ohms on the rear deck and the bolt for the seat belt... then you can very quickly see if the difference is to big