Hey guys,

Today i i decided to change my battery since its struggles, but successfully starts every time i turn on the engine.

I decided to go over to autobarn today and buy a new battery. I bought what was recommended at autobarn. When i put the new battery in, my interior lights wont work but the wipers would and the engine wont turn over when i try to start it.

When i put my old battery back in, weirdy the car starts up quick and healthly, all the electrics were working, EXCEPT the stereo and amps werent turning on...

Very strange, ive checked all the fuses and every seems to be ok, is there anything else i could check before i escalate this to the mechanics?

Did you check the fuses built into the amp? Is there one in the back of your deck, or in the power wire in?

Hey sh00t thanks for your reply

oh yes, ill have to check those inbuilt fuses, but the power cable fuse seems to be ok.

I'd concentrate on the head unit first, the amps probably wont turn on til the trigger wire has voltage...

hey, ive just checked, and found that alll the fuses were blown.... one from the headunit, 2 from the sub amp and 2 from the splits and rear amps....

i dont know weather its my fault or autobarn getting me the wrong battery... what could i have done to blow these fuses while replacing battery?

unless they gave me a wrong battery, if thats the case, reckon i can do anything to get anything out of them?

Just check the battery is correct for a magna, if it fits, and the poles meet the limited positive wiring, its pretty hard to get wrong...
I'd just be happy if it all works again. You could mention it to them, wether they beleive you didn't muck it up is another matter.
I'd replace the fuses and see how it is. If it was all good. I'd let it be..... That's what fuses are for......
Glad you found the issue, hope there's no more in store for you......

It wouldn't hurt check all the pos and neg leads and connectors before you give it another batch of fuses tho.....

The worst fuse to pop, is the ecu fuse in the yellow bracket in the engine bay fuse box, gets a lot people, no matter how careful they are.

wait yeah, all the audio fuses poped,

AND

including one of the 120a fuse under the bonnet. Having trouble taking it out, any tips on doing that? i tried prying it out with a screw driver still wont budge

If you look on the side of the fuse box there will be 2 10mm bolts opposing each other, remove these and the fuseible link will come out.
You sure you didn't get the polarity wrong?

You sure you didn't get the polarity wrong?

Was just about to ask this..... I'd say this is the Reason...

yeah i think i got the polarity wrong...

nooby question, am i supposed to disconnect the wire without the amp wires connected first? and connecting the amp wires first when i get the new battery in?

somebody please clear this up for me

Autobarn probably sold you a battery with the + and - of the thing back to front. Check it against the old battery.

How you connect it up now, which wires go on first, doesn't really matter.

Connecting a battery with reversed polarity is a big No No in automotive electrics. Hopefully the electronics are protected from that, but to blow a 120 amp fuse takes a lot of current flowing somewhere. Hopefully everything works with the right battery, but check your alternator output - the diodes in that don't like reverse voltage! If they blow, there will be no output from it.

yeah i think i got the polarity wrong...

nooby question, am i supposed to disconnect the wire without the amp wires connected first? and connecting the amp wires first when i get the new battery in?

somebody please clear this up for me

Fitting a battery,
if you have amps, remove the underbonnet fuse from the Power cable.

To remove - Earth First
To Fit - Earth Last.
Its just easier when working on the +, that you won't short out against the car.....

Triple Check Polarity...... ( Ooooops, too late)

Thanks guys,

Is the earth the cable without the amp wires connecting to it?

Earth connects to the "-" side of the battery.

Positive (+) must be on the right side, connects to fusebox, amplifers, starter motor.
Negative (-) must be on left side, connects to chassis rail under airbox, bellhousing

Disconnect positive first, negative last
Connect positive first, negative last

Before connecting negative completely when installing again, give it a light tap - It should spark but this gives you a good chance to listen and smell for blown fuses if there are any problems.

Always inspect polarity (which side the posts are on for + and -) before installing.

http://i1191.photobucket.com/albums/z467/Shootmarty/2011-06-09083839-1.jpg

If you are not confident in dealing with the car electrics, get help, they can screw your car up big time, very quickly.

Thanks Life, that made it very clear for me :D



well, i went to autobarn to pick up a replacement fuse, they didn't stock any 120a ones so i bought 100a onse.

I had a crack at installing the fuse and it worked! wasnt as hard as i thought it would be, it was just 2 screws that connected the wire to it.

I started the car and it work fine, the engine would start weakly... it would just go chug..... chug................. chug ............... vrummm
I took it a couple of laps around my area and the car seemed to work fine.

When i went back into my garage, and tried turning it on again, and it wouldnt start!
it just makes a quiet tick noise somewhere under the bonnet followed by a whirr noise comming from the back of the car...

Any ideas or guess what my problem could be?

Check the 100Amp fuse you replaced, it may have blown due to incorrect specs. May also be your alternator may my rooted and not charging the battery.
If you have a multimeter, check the voltage on the new battery, and check the clamps on the battery, are they loose?

Remember when the 120 amp fuse blew? That probably was the alternator diodes getting zapped! Diodes don't like reverse voltage, they erupt like a volcano and spew their innards out!
Worse, if they go closed circuit rather than open, they will draw current all the time and the alternator will get hot even with the engine off while the battery goes flat.

Check battery voltage with a multimeter as suggested, but first disconnect one side of the battery and put it on a charger for a few hours. Once the engine is running, check voltage and feel if the alternator is heating up.