Connecting amp/sub power cable to battery

TheBlackMoth · Post by **TheBlackMoth** » October 16th, 2006, 10:35 am

I am installing an amp and a sub in my car, and I cannot find the hole to feed the power cables into the engine bay to the battery. I have looked behind the battery for the hole, but just can't find anything.

Can anyone help me out here? Is it easier to feed it through from inside the car?

Cheers!

PATDIESEL · Post by **PATDIESEL** » October 16th, 2006, 3:15 pm

Start at the amp and run the wires tword the battery. The hole in the firewall is just below and to the left of the brake booster. You need a grommet to protect the wire so it doesn't get a hole rubbed in the sheething. It is hard to see the hole in the firewall from the drivers footwell so poke a wire through from the engine bay first to make it easier to locate.

jschrauwen · Post by **jschrauwen** » October 17th, 2006, 1:45 pm

Pat I'm not sure if this still applies to RHD MX's since the brake booster should be on the opposite side to the LHD's. But I'm sure they will figure that out pretty quick.

PATDIESEL · Post by **PATDIESEL** » October 17th, 2006, 10:31 pm

Oops,

I have no idea where Guildford is and thus didn't know it was RHD. But... if he didn't/doesn't know what a brake booster is then he shouldn't own a MX-3

Why'd you have to call me out on that

Aston Wards · Post by **Aston Wards** » October 18th, 2006, 11:23 am

there should be a rubber bung in the firewall on the engine side (about an inch in diameter) pull this out and feed your cable through there, the cable should come out in the drivers footwell a lil above the pedals.

Vanished · Post by **Vanished** » October 18th, 2006, 2:40 pm

easiest way to do it:

Go out at night, or turn off the lights in your garage. put a flood light under the steering wheel. Get out of the car, popped the hood, and look for light, and thats were you put your wire. There might be other holes here or there, but the one with a rubber gromet will be your best bet, also the biggest.

jschrauwen · Post by **jschrauwen** » October 18th, 2006, 3:06 pm

Vanished wrote:easiest way to do it:
Go out at night, or turn off the lights in your garage. put a flood light under the steering wheel. Get out of the car, popped the hood, and look for light, and thats were you put your wire. There might be other holes here or there, but the one with a rubber gromet will be your best bet, also the biggest.

Not always going to work. As Aston mentioned in previous post, if it hasn't been tampered with by previous owner there will be a bung (plug) not a gromett. Therefore no light will come through a bung.

TheBlackMoth · Post by **TheBlackMoth** » October 19th, 2006, 8:38 am

Cheers for all the replies guys, to be honest I'm tempted to try the light method at night first, as it'll only take a minute and might save me ten.

I am ashamed to know I don't know what a brake booster is

But then that's why I joined these forums, to learn this kind of stuff!

TheBlackMoth · Post by **TheBlackMoth** » November 2nd, 2006, 7:00 am

I managed to find it, but the hole is too small to get the 1/2 inch wire for my amp in. I did however after a lot of attempts manage to get the 1/2cm wire for my sub through, so I now have the sub up and running (has built in amp)

The only thing is, it pops a few times when I start my engine up... Is this because I have the REM attatched to wrong cable? I can't work out which one is AC++ 12v and which is the Memory wire. Is there a test I can do with my multimeter to confirm which is which?

Cheers,

B.Moth

PATDIESEL · Post by **PATDIESEL** » November 2nd, 2006, 10:46 am

Check that the ground is good and that you used the same size wire as the power wire. Then you need to find the right Rem wire. It sounds like you have the power wire, make sure that is not the case or you'll run the battery down since the amp will draw power all the time. The easiest way to check is to use a mulimeter to look for 12 volts when on (write down all wire colors that have 12 volts, should only be two wires) then turn the car off, only one wire should still have 12 volts, that is the power, the other should be the Rem.

TheBlackMoth · Post by **TheBlackMoth** » November 2nd, 2006, 11:30 am

Sorry, I checked all the connections and realised I had the wires going to the head unit the wrong way around! Guess that must have affected the supply to the sub. Cheers for the help