Electrical fault car won't turn over !!!!! (please read)

[finest1]

hi all,

I was driving to work as normal and I noticed the electric displays in the car getting "dim." I was in local traffic and noticed the car Battery light come on to.  then the sat nav screen went off and I assumed it was the Battery.  the illuminated dials went off too. strangely when I accelerated the displays came back.  anyway later the car had actually switched off whilst driving, no engine no electrics. I managed to coast to the side of the road.

actions:

I called the AA and the chap did his diagnostic. in his opinion there is no mechanical failures of the alternator or starrer motor. he said its electrical. because this was beyond his capabilities, he advised me to find an auto electrician.  further to this when he went to attach the OBD scanner, it couldn't read the port, or maybe no power going into the port.

I'd thought I'd post this in case anyone has experienced this or can lend a hand in troubleshooting. i'll list some observations

when you push the start button only the dials illuminates with the dashboard, no sat nav screen. 

the brake pedal is hard not soft and car wont turn over

yes:

front headlights

hazard lights

dash display

no:

sat nav screen

radio

central locking

power mirrors

rear light

brake lights

any ideas welcome!!

 

thanks in advance

[Hadrian]

Either duff Battery or alternator. (?)

Although many years ago I had a similar problem with an Audi 80.  Everything started shutting down, including eventually the engine.

It turned out the the earth braid from the alternator had corroded through.

[finest1]

thanks Hadrian,

AA guy checked earthing around Battery and from alternator, it passed

not sure if its Battery, as the Battery indicator never lit up previous to this event. it usually does in the past. the AA guy checked Battery also.

furthermore a work colleague helped me by attaching booster cables, for 15 mins

[Herbie]

The Battery is only used to start the car. Once the engine is running and the alternator spinning, the alternator feeds all the car's electrics and keeps the Battery charged.

It sounds like the alternator has failed electrically and the Battery has subsequently gone flat but, before spending any money, I'd check the Battery connections, the starter motor connections, the negative connection from Battery to body and the engine earth strap, all for cleanliness, good contact and tightness.

[finest1]

thanks Herbie, that's what the AA guy done. he boosted the Battery for a while, but car wouldn't start.

I got an auto engineer coming tomorrow, i'll update you how it goes

[BachelorDays]

Hope you get it sorted easily.

The only way the AA guy can be sure the alternator and starter motor are fine is by testing them and I'm not too sure how he could do that with a non-runner.

Ideally the Battery should be charged (or a fully charged battery/ very heavy booster used) before further investigation.  If the engine cranks that means the starter is functioning - otherwise the fuse/solenoid on it could be blown and that will cause charging errors.  If the alternator is gone the car will start with a good Battery.

These are basic checks - an auto electrician will go through these as standard.  If it isn't the alternator (because it does sound like it) it could be a relay.  The voltage running down would probably have caused a few other fuses to blow which would explain some lights and functions not working.  If it is a relay do ask the guy why it has happened - happens once, will happen again unless underlying issue is resolved.

Haven't had the engine bay washed recently or such?

[finest1]

hi all, I thought I'd give you an update:

the diodes on my alternator had slowly started to burn out over the years. this overloaded the secondary fuse box and caused a short circuit. so it was the relationship between the alternator and the actual fuse box. I must say the auto electrician was brilliant! he also reconditioned the alternator for me.  car is purring again this morning!! the actual cause: wear and tear, he highlighted the fact that the car is 12 years old and parts would age.

 

thanks for your contributions

[Texas]

Good result for you there then, could have been a lot worst I guess, imagine giving it to Lexus and saying fix this please (£££££'s)

Agreed electrical components do age/wear and not necessarily with use, I see you got nearly 120k under your belt and hopefully I don't encounter this problem any time soon with my 40k but It's the age thing that may be more pressing as I read on the LS section there are problems with capacitors 'bleeding out' and failing on ECU's as these cars are now over 30 years old!

paul m.

[finest1]

hi texas,

yes, speaking to the auto electrician he said that generally Lexus are well built cars, with very little issues. when there is an issue it can be diagnosed quickly. in the 8 years I've had the car this is the only major issue I've ever had where the car broke down on me.  in my case there was no warning at all, it just konked out.  he actually kept the old diodes shoe to show me where it had slowly burnt out.  yes the repairs could have been a joke, but both ways I needed an auto electrician to give me a report as to what is going on before making a decision. he was really informative, no dramas, honest and upfront. he's definitely someone im going to use in the future!!  when I asked him if this would happen again, he said there is no guarantees on any car at any age.  for this to be the only major incident in the 8 years of this car, im fortunate!

[Chris JJ]

On 11/13/2018 at 9:03 AM, finest1 said:

hi all, I thought I'd give you an update:

the diodes on my alternator had slowly started to burn out over the years. this overloaded the secondary fuse box and caused a short circuit. so it was the relationship between the alternator and the actual fuse box. I must say the auto electrician was brilliant! he also reconditioned the alternator for me.  car is purring again this morning!! the actual cause: wear and tear, he highlighted the fact that the car is 12 years old and parts would age.

 

thanks for your contributions

Hi would you PM me his details hard to find a decent auto elec guy please