PLEASE HELP

[Doriantaylor123]

I have a 2002 lexus is200se

A few days ago I was driving and all electrics went down

The car still starts and i have headlights, hazard lights and dome light

I have no power to the windows, sunroof, radio, indicators, speedometer rev counter, back lights brake lights etc

I have checked every fuse and they are fine

If I red line the revs in neutral I get a little bit of power to the dash

 

Any ideas?

[Herbie]

I think I'd disconnect the Battery for a few minutes as it may reset something but it may be one of the master fuses.

[bobmc]

I'd suggest the alternator is the 1st place to look - headlights, starter motor, hazards all seem to be wired as essential systems, radio, wndows etc as secondary systems. 

Check voltage across the Battery terminals with/without the engine running. It should read higher when the engines running

 

 

[Doriantaylor123]

Herbie I did that and no joy

Bobmc I was thinking alternator. My theory was that the essentials would still run like you said and the rest being secondary wouldn't. Thanks for the advice I will let you know how I get on 

[Herbie]

It is possible that it's the alternator but somehow I doubt it.

The alternator only comes into play once the engine is running and it feeds all electrical circuits first, then if there's enough power left over (so to speak) it will charge the Battery.

If the Battery still has enough power to feed the starter motor (draws about 300A on cranking) and fire the engine, it should also power the radio etc. Does the radio work without the engine running?

I don't know of anything in a car that is intelligent enough to decide what needs power and what can do without it, so my money is still on a major fuse. Having said that though, how have you tested all the 'normal' fuses - just by looking at them or by checking continuity with a multimeter? Multimeter is the only reliable way really.

EDIT: Also possibly a bad earth somewhere. Take off and clean both the main earth strap from Battery to body and also the engine earth strap too.

[steve2006]

Have you also checked the engine bay fuses, these tend to be a higher current rating and power multiple circuits, a common failure is the alternator fuse usually rated around 120A, this type of fused is hardwired so you cannot simply pull them out to check but the top cover is clear so you can see if the wire is broken inside.