Fuse identification

lazzlo amundo · March 29, 2019

This is the main fuse box bottom pic,the fuse with the green arrow stops the drain when i pull it.That's the dome fuse,this is the fuse that stops everything working

in this fuse box top pic.

.

lazzlo amundo · March 29, 2019

18 minutes ago, lazzlo amundo said:

This is the main fuse box bottom pic,the fuse with the green arrow stops the drain when i pull it.That's the dome fuse,this is the fuse that stops everything working

in this fuse box top pic.

.

https://drivers.lexus.com/t3Portal/document/om/OM50434U/pdf/6-4.pdf

lazzlo amundo · March 29, 2019

3 hours ago, runsgrateasanut said:

Did you establish that your CD player in the boot opens?

Its a permanent "live" and if it isn't working then you need to check the cable routing.

Is it a 15 A fuse to the Fusebox? Seems low to me as Heater is 20A? Doesn't answer your drain problem given what you say.

No the cd player doesent open,i presumed it was because the radio doesent work.All the fuses are ok.I think your right,this is where the problem is.

Herbie · March 30, 2019

Cliff, you say that when you pull fuse No. 20, the Dome fuse, rated at 15A (which should only be 10A), it stops the Battery drain. That's good as it gives something to work with.

However, you also say that it stops everything in the driver's footwell fusebox from working. That's bad because fuse 20 has got nothing to do with the fusebox in the drivers footwell.

None of the items listed above from the pdf document you uploaded, tally with the items listed on the fusebox cover from the drivers footwell below, so the Dome fuse can't have a bearing on them:

Something is wrong somewhere and if pulling the Dome fuse really does stop everything in that fusebox working then it's going to be difficult to sort out.

runsgrateasanut · March 30, 2019

Did you establish that when the Radio was completely disconnected that there was no longer a drain on the Battery?

The Fuse marked in Green number 20 looks like a Blade fuse and not a Dome fuse - maybe I misunderstand the terminology here as I thought Domes were the square box fuses.??

20 Is a fuse that affects the power to the Radio, the CD changer and numerous other things. When the Radio is disconnected and the fuse in situ, does the rest of the things listed work?

As I said, the CD changer is a permanent live and I imagine it runs via the loom to the Radio and then out to the Changer etc.?

The Radio is not a permanent live, but only via the ACC and ignition. You need to check the wiring to the CD changer to see if it has a fault.

Herbie · March 31, 2019

15 hours ago, runsgrateasanut said:

The Fuse marked in Green number 20 looks like a Blade fuse and not a Dome fuse - maybe I misunderstand the terminology here as I thought Domes were the square box fuses.??

The word 'Dome' usually refers to the dome light, the overhead light that comes on when you open doors, rather than a description of the fuse itself, as you'll see from this:

runsgrateasanut · March 31, 2019

I've pm'd you Cliff, but I'll also wirte down here in case someone may have a comment to make.

I've at last connected that spare Radio to my wiring.

The good news is that it works. The bad news is that I don't know for certain what works as the Radio has a security code that needs to be put in.

Having taken it out and put all the gubbins back, and as I write this email I seem to recall that a code of 0000 may have been the default code for Radios. Sorry I didn't even try at the time and can't be bothered to pull everything apart again. So, if its fitted into your Car it should at least show SEC on the display to know that you now have a Radio that doesn't drain your Battery. The serial number data is on the Unit and you may find out online how to "unlock" the unit.

lazzlo amundo · March 31, 2019

Look at this silver thing above my cd player,when i unplug it my engine stops,anyone know what it is.

runsgrateasanut · March 31, 2019

Could it be a tracker? Havn't a clue - I've answered your pm.

Herbie · March 31, 2019

53 minutes ago, lazzlo amundo said:

Look at this silver thing above my cd player,when i unplug it my engine stops,anyone know what it is.

Zooming in on the right-hand side you can just about make out the number 89570-50010, so Googling for that shows that it's the fuel pump ECU:

https://www.ebay.com/itm/1993-94-Lexus-LS400-Genuine-Fuel-Pump-Control-Module-89570-50010-/122892036982

lazzlo amundo · March 31, 2019

On 3/30/2019 at 12:38 AM, Herbie said:

Cliff, you say that when you pull fuse No. 20, the Dome fuse, rated at 15A (which should only be 10A), it stops the battery drain. That's good as it gives something to work with.

However, you also say that it stops everything in the driver's footwell fusebox from working. That's bad because fuse 20 has got nothing to do with the fusebox in the drivers footwell.

None of the items listed above from the pdf document you uploaded, tally with the items listed on the fusebox cover from the drivers footwell below, so the Dome fuse can't have a bearing on them:

Something is wrong somewhere and if pulling the Dome fuse really does stop everything in that fusebox working then it's going to be difficult to sort out.

5 hours ago, Herbie said:

The word 'Dome' usually refers to the dome light, the overhead light that comes on when you open doors, rather than a description of the fuse itself, as you'll see from this:

It is a blade fuse,number 20-dome,it had a 15 amp in there but iv'e put a 10 amp in now.The ign light is on the list,if the fuse knocks the ign off then nothing will work..i'll have another go in the morning.Iv'e got head ache and brain freeze.

lazzlo amundo · March 31, 2019

6 minutes ago, Herbie said:

Zooming in on the right-hand side you can just about make out the number 89570-50010, so Googling for that shows that it's the fuel pump ECU:

https://www.ebay.com/itm/1993-94-Lexus-LS400-Genuine-Fuel-Pump-Control-Module-89570-50010-/122892036982

Thanks Herbie,now i know what it is.

Herbie · March 31, 2019

21 hours ago, runsgrateasanut said:

20 Is a fuse that affects the power to the Radio, the CD changer and numerous other things. When the Radio is disconnected and the fuse in situ, does the rest of the things listed work?

From the list of fuses, the first one, Fuse No.18, labelled 'Radio No.1' and rated at 20A, is for the radio/CD so I would guess that this is the main 'working' fuse for the radio.

Fuse No.20, the 'Dome' fuse feeds, amongst other things, the interior 'dome' light, the ignition switch light and the radio/CD.

Because the ignition switch light only has one purpose in life - to allow you to see where to insert the ignition key when it's dark - it must have a permanently 'live' supply to do that, so I would hazard a guess that Fuse 20's connection to the radio/CD is to keep the radio presets in memory while the ignition is off.

If I'm correct in my assumption that Fuse 20 provides a permanent live feed, then with the radio disconnected but the fuse still in circuit, everything else it feeds such as the interior light, the ignition switch light light etc., should still work.

But none of that answers why, when Cliff pulls Fuse 20, does everything in the drivers footwell fusebox go off?

lazzlo amundo · March 31, 2019

35 minutes ago, Herbie said:

From the list of fuses, the first one, Fuse No.18, labelled 'Radio No.1' and rated at 20A, is for the radio/CD so I would guess that this is the main 'working' fuse for the radio.

Fuse No.20, the 'Dome' fuse feeds, amongst other things, the interior 'dome' light, the ignition switch light and the radio/CD.

Because the ignition switch light only has one purpose in life - to allow you to see where to insert the ignition key when it's dark - it must have a permanently 'live' supply to do that, so I would hazard a guess that Fuse 20's connection to the radio/CD is to keep the radio presets in memory while the ignition is off.

If I'm correct in my assumption that Fuse 20 provides a permanent live feed, then with the radio disconnected but the fuse still in circuit, everything else it feeds such as the interior light, the ignition switch light light etc., should still work.

But none of that answers why, when Cliff pulls Fuse 20, does everything in the drivers footwell fusebox go off?

Good news,when i pull number 20 fuse most things still work.the things that don't work are.dome lightes,door lightes,glove box light,ign switch light,centeral locking and steering wheel.motors.It' got to be one of them that drains my Battery.It could be something to do with remote locking,i haven't got a remote key so i can't test that.

Herbie · March 31, 2019

So just to confirm - pulling Fuse 20 does not stop the fusebox in the drivers footwell from working? Is that correct? And if the answer to that is yes, what initially made you think that it did and why have we been pulling our hair out trying to think of reasons as to why that should be? :wallbash: :rolleyes1: :laughing:

lazzlo amundo · March 31, 2019

16 minutes ago, Herbie said:

So just to confirm - pulling Fuse 20 does not stop the fusebox in the drivers footwell from working? Is that correct? And if the answer to that is yes, what initially made you think that it did and why have we been pulling our hair out trying to think of reasons as to why that should be?

It was a few week back when i was trying to figure out things,it was freezing cold and damp.I was tired,my old bones was hurting some what.I must have just turned the key one click and saw no ign lights,tried my sun roof and windows then put the fuse back in.Human error,and i do appologise.I was just thinking the worst,i always do.Sorry.

Herbie · March 31, 2019

No worries Cliff, that's why I finished off with a laughing face emoji - we all make mistakes my friend.

At least we're one step closer to solving the mystery.

runsgrateasanut · April 6, 2019

I've PM'd you.

runsgrateasanut · April 7, 2019

On 3/29/2019 at 7:32 PM, runsgrateasanut said:

Did you establish that your CD player in the boot opens?

Its a permanent "live" and if it isn't working then you need to check the cable routing.

Is it a 15 A fuse to the Fusebox? Seems low to me as Heater is 20A? Doesn't answer your drain problem given what you say.

I photo'd this a couple of years ago when I thought it might be the fuse had blown for my Cigar lighter. Couldn't get the cover to move and as have sciatica I photo'd to try to tell how the cover came off. At the time i found it was the fusible link in the lighter which was burnt out. Could your lighter if it doesnt work be the source of your drain, perhaps? They commonly don't work becuase of that link.

Did you discover how to remove this cover? Are those two clips that need pushing in, or what? I've definately blown the fuse in my lighter which is a poor design in terms of insulating the pos from the neg. so need to try to get at the fuse. Will be fun!

Haashiem · January 20, 2021

Hi i have a lexus ls400 1999 model guys i had a problem with my cigarette lighter so i checked the fuse box under the dash so i checked all the fuses and after that i was sitting with a problems it seems like the car is misfiring splutter a bit on start up and when i rev it up its not reving clean

Haashiem · January 20, 2021

7 minutes ago, Haashiem said:

Hi i have a lexus ls400 1999 model guys i had a problem with my cigarette lighter so i checked the fuse box under the dash so i checked all the fuses and after that i was sitting with a problems it seems like the car is misfiring splutter a bit on start up and when i rev it up its not reving clean