major electrical fault, help me!

[VB-]

well, i just got home to find out that ma mums car dont start, and the guy from RACV diagnosed it as an 'electrical fault', im guessin a short circuit sumwhere, but not sure : . its an EA 50th anniversary 3.9 (not multipoint)the symptoms are as follows:

car wont start
light beside tailgate switch keeps flashing (the lock/unlock switch on the dash)
right indicator comes on
nothing displays on radio face, but backlight comes on
central locking tries to lock the car intermitantly

i dont know anything about the immobiliser, and have no idea where it is exactly. the alarm has been disconnected coz it went off one day a few years back, and we just cut all the wires off the back of it to shut it up. theres a seperate switch hidden away to kill the imobiliser, its not a remote key for the alarm and imobiliser (hence just ripping the alarm out as we couldnt stop it : ) so normally we can start the car if the immobiliser does kick in for whatever reason.

i have quite a good understanding about cars, but not this side of it, so gurus, please help :

PS sorry if this is in the wrong section

[EFFalcon]

ground problems
fuse problem

they're the easiest things to check.

[LTDHO]

VB.

Was the alarm removed or bypassed? Was it done properly.?
What happend when key turned to 'ON'?
What happens when key turned to 'START'?
How good is the battery?

[VB-]

what fuse/relays would i be lookin at thats on the same circuit as the immobiliser, indicators and central locking? the grounds have never really been that good, they been crap for years, but it just happened today, i dont think they coulda got that much worse, but i'll still check

[VB-]

LTDHO, the alarm was ripped out years ago by cutting the wires, on the back off it, unbolting, and throwing it in the bin, the immobiliser has not been touched. ma mum just went out today, then couldnt start the car when she tried to come home, racv just shorted the battery directly to the starter motor to get it goin, she got home and told me. when the key is in the acc position, its kinda normal, accept there is no display on the head-unit, just the backlight comes on, and the normal dash lights come on, park break, when i hold the key forward on start, the brake fail light and check engine light i think come on, just like normal when starting the car. the battery should be fine, theres been no trouble starting it, and no signs of it dying. also, the right indicator comes on, but it will keep flashing till the door is closed.

[VB-]

ok, so i've done some of my own diagnostic. it would seem that ANYTHING that makes an electric circuit, will cause the right indicator to flash for about 30 secs. this includes opening doors, opening glovebox (coz its got that little light inside) opening tailgate, just about any switch on the dash will set it off, except the head-unit, this seems to have no effect on it what so ever. the doors locking emselves is very random, and i have no idea wot causes htis.

i have found that when the right indicator comes on, its not on the indicator circuit, its on the hazard circuit, and there is nothing i can do to stop em flashing. nomrally u can do anything, it will flash for 30 secs, but if u dont turn on/off, open/close anything, it will stop after the 30 secs, but if the bonnet is open, it will go for 30, stop for about 5 or 10, then start again.

i've pulled out just about every realay and i cannot stop it (four next to all the fuses, four under the bonnet.

as for the dash lights, its the battery and park break that come on when on acc, and the park break and brake fail when turning key to start.

[AshMan]

Get a multimeter and put the positive probe in your radiator coolant, and the negative probe on the negative battery terminal.

Set it to the 10 amps scale.

If you get a reading, it means you have a dud ground somewhere.

[VB-]

if it was ground tho, would it caus indicators to turn on? while everything else still works, including radio? and would this cause the imobiliser to constantly cut in? what is that light for next to the tailgate lock/unlock switch anyway?

[HSVETAR]

Well the ground/earth is also the negitave, if you look you will see that the negitave battery terminal is linked straight to earth. The negitive cable from the indicator is bolted straight to earth, which is a negitive return. Get your mulitmeter and put the switch on 10k ohms, check between the negitave terminal and earth (it should read infinity) that means the earth is ok. Check between earth and positive (there should not be any reading) if so there is a short somewhere. Check that and post back.

[Stav]

You have a flat battery.

[VB-]

i'll have to get a hold of a multimeter and do some testing. are these common symptoms of a flat battery useless?

[Stav]

99% of car alarm faults are a flat battery.Do your headlights work? Do they stay on when you try to crank the car ?

[VB-]

i cbf waitin for a multimeter, so i just went out n started probing things. turned out to just be a grounding problem. i was gonna take the battery out and realised just how much there was on the terminals, gave it a quick clean and its all good. dodgy grouding probly explains the randomly dimming lights ma mum told me about... doh! thanks for the help guys

[Jet-Star]

Originally Posted by VB-

i cbf waitin for a multimeter, so i just went out n started probing things. turned out to just be a grounding problem. i was gonna take the battery out and realised just how much there was on the terminals, gave it a quick clean and its all good. dodgy grouding probly explains the randomly dimming lights ma mum told me about... doh! thanks for the help guys

And the RACV bloke didn't notice this when he was bi-passing the battery to the starter? haha...Oh well least it didn't cost you an arm and a leg to fix in the end.

[VB-]

yeh i mean damn, ma mum said he actually tested the battery and said it was fine, still didnt notice the crap on the terminals, and he had the benefit of working in daylight.... i know an auto spark anyway, so it wouldnt have been a big issue, just didnt want to ask the favour, plus this way i have the satisfaction of knowing i fixed it myself lol

[sphell]

I swear, half these RACV guys are so useless. I mean that should have been the second thing he checked. First would have been to see if it was a flat battery.

Also what Useless said about car alarm probs is soooooo true. Don't u just hate it when u get a customer that swears black and blue that it's the immobiliser cutting in when it's just a flat battery! Drives you insane trying to convince them otherwise!

[HSVETAR]

Good stuff dude. THese RACV guys must be pretty useless.