anyone familiar with vehicle stereo wiring? poss bad ground/earth

MTI · Jun 8, 2009

hi all, please can anyone help me. im in desperate need of fitting my bluetooth parrot im my new(ish) van to allow hands free telephone calls.

basically my first problem is the factory stereo. this seems to be broken so i have tried to fit my own after market unit. im quite familiar with all connections and have bought the correct wiring harnesses etc. obviuosly ill need a stereo to allow sound through speakers etc and just as importantly - entertainment!

ok, so the wiring and fuses are all fine, sometimes the stereo will turn on and operate and most times- nothing at all! dead!

constant supply and switch live etc is ok and getting 12v between sources and ground terminal without fail.

when you put meter across terminals with no load = 12v

connect radio on and voltage drops to about 2v or less?

could it be bad earth/ground return?

van is only couple of years old with no visable damage or rot etc. only done 14,000 miles.

any advice is most appreciated well in advance all!

kindest regards, martin.

daniel hill · Jun 8, 2009

check all of the earth terminaly and check that the wires are all in the crimp lugs wen are bolted to the body also check the main earth on battery

danny

MTI · Jun 8, 2009

cheers danny. done all the above already. still fails to work and all seems well. nothing else is faulty at all, nor dimm etc

lister · Jun 8, 2009

First off you dont need a stereo to fit your parrot only speakers, as this interupts radio to speaker wiring upon use.

fault really does sound like bad earth, had it before in terminal block - is it a vauxhall?
try earting stereo direct to casing and let us all know.

daniel hill · Jun 8, 2009

there will be 2 plugs

speakers and power
the speakers consist of 4 wires or maby 8 if has 4 speakers in it but you can forget that plug

in the other plug if i think right there should be a black that is your earth and and a red thats ignition live and a yellow that is constant live

with a test lamp check that you have a good live and a good earth dont use a tester as sometimes they dont pick up the earth to good when checking it

have had this a few times on cars as dad is a full time mechanic in leeds just normally solder a new earth piont and take it to the battery or to a clean bolt on the body

MTI · Jun 8, 2009

lister said:
First off you dont need a stereo to fit your parrot only speakers, as this interupts radio to speaker wiring upon use.

fault really does sound like bad earth, had it before in terminal block - is it a vauxhall?
try earting stereo direct to casing and let us all know.

as a matter of fact - yes vauxhall combo van! typical of vauxhall. also now causing dashboard digital display to play up (vauxhall dont have screens on radios).

im going for the bad earth too. all else is well. there is a very very shiny metalic strut which braces the dash etc in event of a smash. i reckon ill be firing a self tapper into that first thing in morning. yellow eye crimp and 4mm earth should do it nicely

there is also only a red feed (perm) and a black as ground on vauxhall so im gonna take the ignition switch live and lighting switch feed from there - two birds in one!

funny- vauxhalls cig lighter feed is switched with ignition so you cant leave something plugged in and drain battery - stupid for charging phone etc in glove box when not in car!

also, perm feed to radio only but yet it has ignition recognition from just the one feed? madness!
the loom is now wired to stereo first from fuse box apperently on all new cars? if so, ever got an elec problem on car - take large hammer to stereo first lol!

cheers all so far!

also, yes - the parrot doesnt need stereo connected as it just cuts into speakers, however it does make you loose digital dash. not overly important i know but annoying without it. especially when i forked out £30 quid for wiring harness in eagerness to do it over the weekend. ebay = £5!

cheers for all your inputs guys! typical only one thing playing up and not loads or the 'loose ground conection' may of been easier to locate. anyway, im glad its only the one thing and not tons come to think of it.

daniel hill said:
there will be 2 plugs

speakers and power
the speakers consist of 4 wires or maby 8 if has 4 speakers in it but you can forget that plug

in the other plug if i think right there should be a black that is your earth and and a red thats ignition live and a yellow that is constant live

with a test lamp check that you have a good live and a good earth dont use a tester as sometimes they dont pick up the earth to good when checking it

have had this a few times on cars as dad is a full time mechanic in leeds just normally solder a new earth piont and take it to the battery or to a clean bolt on the body

cheers for that matey. ill bare that in mind. nothing else playing up and battery is good so probably dont need to double up earth to battery. im also in leeds so good to know! cheers daniel

lister · Jun 9, 2009

just double check, but on vauxhall black was live neg/ground was brown depending on year, just verify before connecting.

MTI · Jun 29, 2009

hi all, sorry been away for a while. thanks for all the replies in this post.

So, its now at the stage of total baffleness!

my factory vauxhall stereo did work before removing but now doesnt aknowledge anything. all fuses are fine in fuse box and on back of stereo. they dont have code as they have software which links to ecu only allowing use in that vehicle.

my second stereo (also working when removed from another car a few weeks back isnt working either. at one point i had installed it new van and it kind of flashed on, dimmed a bit and died!?

i dont want to believe that both stereos are dead and this theory just seems insane that two radios, sat in the house together, dry and comfy for a few weeks just give up the ghost.

i have connected ignition switch and lighting feeds to new radio and it illuminates with headlights etc but doesnt turn on with ignition.
tried this also with a new battery feed staright from battery to radio and the same happens.

im sure the battery is sound and is fairly new plus, their is a healthy supply at radio end with existing factory wiring.
its when i put meter on and get 12v and then proceed to plug in radio that the meter drops to about 2v. have not tried a test lamp as yet as not had one to hand but if i have 12v across existing leads and i even added a fresh negative/earth from battery then surely this would/should cure it?

a fail to believe that two stereos are now faulty since being removed.

dashboard clock is also playing up but not sure if this could cause it? i cant see how the factory stereo turns on with ignition when i only have one permanent feed there in the first place. it must have something to do with the 'other' smaller set of leads which are also connected to the harness. think im going to have to pay top dollar for this sorting but id appreciate any help in the meantime as money is tight.

kindest regards, martin