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Toyota Service
Toyota Service, Lexus and Toyota expert
Category: Lexus
Satisfied Customers: 4598
Experience:  30 + years of experience; Multiple Award Winning Svc Mgr; Just Answer Customer's Choice Award Winner
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ES300: Car electrical components stay on after the car is

Customer Question

ES300 : Car electrical components stay on after the car is turned off and the key is removed. Windows work, dash lights stay on, temperature console screen is on, oil warning light comes on, I can move shiftier to drive (with foot on break). Only the radio turns off and on with the key on and off position. The car starts and runs fine. I have replaced the ignition switch and the (body control module/ fuse junction box). Note: I also tested by disconnecting the 2 connectors that go to the ignition switch behind the key cylinder and all the electric components still stay on. My guess is theirs a short in the ignition harness. I need help troubleshooting and an electric diagram would be nice.

Submitted: 9 months ago.
Category: Lexus
Expert:  Ron replied 9 months ago.

Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

If you can tell me what model your Lexus is I will locate the wiring diagrams you need and see if I can help you determine the cause. Post back when you can and we can work from there.

Customer: replied 9 months ago.

Hi Ron, The car is a 2002 Lexus ES300

Expert:  Ron replied 9 months ago.

Okay there are 3 diagrams that cover the power distribution. See this in the link below, copy and paste them to your browser to open and view them. See if this will help you find the source of the short to power.

https://dl.dropboxusercontent.com/u/104923897/Power%202%20Feb%2010.pdf

https://dl.dropboxusercontent.com/u/104923897/Power%203%20Feb%2010.pdf

https://dl.dropboxusercontent.com/u/104923897/Power%20Feb%2010.pdf

Customer: replied 9 months ago.

Thank you for the drawings. Is it possible that a relay is stuck closed?

If so would you know which it could be?

I see relay 1G1 and ACC in the drawing but not sure of there location in the car. Note: I have pulled all the relays in the engine fuse block one at a time but all electric remained on.

Expert:  Ron replied 9 months ago.

Yes its possible or you have a short to power in the wiring. This type of problem can be a bit hard to chase down. If you look at the diagrams you will see the location of the relay as they are marked as to where there location is. I would start by unplugging them one at a time.

Customer: replied 9 months ago.

It looks like you posted two of the same diagrams. I think I'm missing one.

Expert:  Ron replied 9 months ago.

Try this one.

https://dl.dropboxusercontent.com/u/104923897/Diag%202%20Feb%2010.pdf

Customer: replied 9 months ago.

Hi Ron, I removed all the relays on the interior J/B (the IG1 and ACC relays ) and the dash board still lit up. How should I proceed. FYI- no rush getting back to me, I can't work on it tonight.

Expert:  Ron replied 9 months ago.

Something has to be feeding power into the circuit. Did you try removing each fuse one at a time ?

Customer: replied 9 months ago.

I removed all the fuses and all the relays from the drivers side interior J/B.

I removed all the fuses from the engine compartment left hand side J/B.(except the 100A and one other) shown in the picture. Rather then take apart the J/B to remove them I disconnected the power lead to the engine compartment Junction box.

After doing all of the above, including disconnecting the power cable to the J/B the dash lights stayed on but things like power windows no longer worked.

I think the above ruled out any short coming from a wire getting power from the engine J/B or interior drivers side J/B. Where else and what else get power from other places or what do you think I should try next.

Note: With all that disconnected, Dash board instrument panel is lit up and hazard lights and blinkers work.

Expert:  Ron replied 9 months ago.

Unfortunately from here its very hard for me to say. If you would like , I can open the post up and we can see if any other have something new to offer.

Customer: replied 9 months ago.

What I'm thinking is that one of the wires that feeds power to equipment and also the power flow to open a lot of the relays is short to power from a wire that is hot all the time such as hazard switch or something else that will work normally without the car on.

What I would like to know is where those things get power from. As an example the hazard lights worked even after I disconnected the engine J/B power lead. Would you know what other source of power there is that don't go through the engine J/B or the drivers side interior J/B ?

Also I like the idea of opening it up to others and I understand that electrical issues can be difficult if not impossible to do remotely.

Expert:  Ron replied 9 months ago.

Doing so now.

Expert:  Toyota Service replied 9 months ago.

Hello. Different expert here. If you still need assistance with this request please advise. I will be glad to help

Customer: replied 9 months ago.

Yes I still need help. here is a summery of the issue and what I've done.

Issue:
ES300 : Car electrical components stay on after the car is turned off and the key is removed. Windows work, dash lights stay on, temperature console screen is on, oil warning light comes on, I can move shiftier to drive (with foot on break). Only the radio turns off and on with the key on and off position.

What I've Done:
1) Replaced the ignition switch, Turned the switch manually, disconnected harness to ignition switch. No change
2) Replaced the interior Junction box completely including BCM, Relays and fuses(drivers side under steering wheel) no change.
3) Removed all fuses one at a time from the engine compartment junction box.
4) Disconnected the power lead to the engine compartment junction box. Many things stopped working like windows, lights etc But the dash board instrument panel was still lit up.

Expert:  Toyota Service replied 9 months ago.

As I understand it, your electrical accessories (that are supposed to be inactive with the key off) are working. Is this correct?

Customer: replied 9 months ago.

yes with the exception of the radio.

Expert:  Toyota Service replied 9 months ago.

Please advise if you have disconnected the ignition wiring connector from the back of the ignition switch and the problem continues.

Customer: replied 9 months ago.

Yes I have and the condition continues with it disconnected.

Expert:  Toyota Service replied 9 months ago.

There are two larger relays on the fuse panel under the dash. Identify them by looking to see that they have 4 pins, and the pins are configured in a north, south, east and west pattern. Remove both relays and advise if the situation continues.

Customer: replied 9 months ago.

I have removed the 2 relays, each had the 4 pins as described above and were attached to the back of the interior fuse box.

With both relays out the electrical components remained on.

Expert:  Toyota Service replied 9 months ago.

One of those two relays is responsible for powering up the fuse panel. If the fuse panel is powered (and your accessories remain on), with main relay disconnected, there is a problem inside the fuse panel. Removal of the relay eliminates the power going to the accessory section of the panel. All of the units that are supposed to be off, with the key off, are on this section of the fuse panel.

Customer: replied 9 months ago.

I have replaced this fuse box on the advise of a different engineer.

(I replaced the entire fuse box and all the fuses and relays attached to it).

Expert:  Toyota Service replied 9 months ago.

That does not mean the replacement panel is good.

Customer: replied 9 months ago.

True, but what are the odds they both would have the same unusual issue. I do think it is possible and its also possible that something could be causing the fuse box to break there by ruining both of them and a third if I install another one .

What is your advise here, replace the fuse box again ?

Expert:  Toyota Service replied 9 months ago.

My advice at this point would be to test the 4 sockets under each of the two relays. See if any have power with the key off (relays removed). If so, we will proceed from there.

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