ahhh, thank you for that info! i should have read the manual. I will test it again today with the headlamps turned manually on (we typically leave them in auto).

 

2011 GX460 Premium. Came with trailer wiring and connectors factory installed.
Trying to install my Tri-Lift Company (mobility chair lift that plug into the trailer hitch) for my Jazzy Select mobility chair.

The Tri-Lift unit pulls 10 amps (fully loaded with the Jazzy Select on it) from a stand alone auxiliary battery used to test this lift with the chair.
I want to plug the Tri-Lift power connection into the 7 pin trailer connect + and - auxiliary power that is available when the GX460 is running.
I see power on those + and - pins.
The manual says I can draw 30 amps from there I think, but it is not clear in the manual.
The manual talks about trailer fuses but not for the + and - pins on the 7 pin connector.
I put a meter on the + and - pins of the 7 pin connector and pulled fuses but none shut off power when the fuse was pulled.
The manual is totally inadequate.

Tri-Lift wants the fuse changed to a 40 amp fuse only because there is a surge when the Tri-Lift motor initially starts up, after that the draw is 10 amps or less continuous when the Tri-Lift unit motor is running.

QUESTION
Where is the fuse for this 7 pin connector + and - output ? The manual does not help me.
Please be specific. I am physically limited and need precise instructions.
What is the rating of the fuse ?

I tried Googling and got no where.
I tried to ask the my Lexus service center about this but they did not know.
They have not been helpful so the next Lexus I buy will be from another dealer.

Thank you.

 

I'm just going off owner's manual at this point. My paper bound wiring manual is not available to me at the moment. I need to see if something more definitive shows up in my electronic versions.

In the under-hood fuse box on drivers side in front of master cylinder see if the following fuses are for that power:

6, 15, 34, or 48

These are all 30 AMP circuits as well.

 

I saw that SUB BATT but did not know how to pull it out. Manual is NOT clear as to the function.

How do I pull that out to check and if necessary to replace ?
It looks like a bank of three fuses or what is it ?
Never seen anything like it before.

I assumed it was for charging a battery in the trailer.
but now it seems it is the supply power to the + and - pins on the 7 pin connector.

Thank you for your help !

 

2011 GX460
In the front fuse box there are fuses and relays.
The single fuses are easy to pull out using the provided puller tool found inside the fuse box.

However, there are some other type of fuses I am not familiar with.
For example fuse 6 the SUB BAT 30A fuse.
They look like a long box with maybe several fuses inside.

How do I get these out and what are they ?
Are these some kind of slow blow fuse or what ?

This circuit goes to the trailer 7 pin connector + pin.
I need to change that to a slow blow or 40 A fuse.
What is connected to the + pin at the hitch is a motor that surges at start but only draws 10 A continuous.
So the fuse needs to handle the very short surge current.

Also, how are the relays removed ?

 

While changing to a slow blow fuse to address momentary current spikes is an acceptable solution, never ever increase the current rating of a fuse over what is indicated on the fuse box cover / owners manual / service manual. Fuses are specifically sized to protect the current carrying capacity of the wiring (gauge) in the circuit they are protecting. To increase the fuse rating could potentially result in a “Carbeque” if a short circuit occurred in the future.

 

You did not help me.

How do I pull that fuse ?
It is not a simple single fuse. I am not familiar with this type of fuse.

I will do more damage to the fuse and fuse block if I do not know how to get that fuse out properly.
10 amperes over the rating will only cause the wire to be some warmer with hig current.
However there will not be continuous draw above 10 amps so there are no worries.
A short will take out the 40 A fuse before any damage to the fuse box or wiring.
And since it is a surge when used as needed, no physical harm will be done to the fuse box or wiring.
But this will keep me from having to change the 30 A fuse too often due to stress on the fuse from the surge.

 

I actually did help you ... but you may be beyond saving. Pulling fuses is one thing, but exceeding the current rating of any circuit is dangerous ... you are playing with fire ... literally.

 

Methinks you need to spend a bit of time learning how this stuff works before you start swapping out fuses *****-nilly.

 

I am a professional electronics design engineer for a huge aerospace company. I know what I am doing.
Obviously you do not. So stop your inane comments.

So please answer my questions or bug off !

I am not familiar with auto fuses.

How do I remove that particular fuse 6 the SUB BATT ?

How do I pull relays ?

 

The 737 Max ? ... now understand why pulling a fuse is so confusing

 

inrush current should be dealt with by using a slow blow. Increasing from 30 to 40 A will allow continuous current above the design safety margin. As said earlier the fuse value is to protect the wire. Yes if its only a quick inrush, then not a problem. the issue is what happens when there is a continuous problem, such as a failure of whatever causes the inrush current, and this failure draws 39 amps? Yes, a direct short should blow the fuse, but there are many other types of failures.

I dont think you can know that the 10 amps will only cause the wire to be somewhat warmer without knowing more about the circuit. And its most likely not the wire that is a concern, it is the contacts, terminals and crimps. The wire itself has a low resistance but other areas do not. The increased resistance generates more heat than the wire.

most fuses either pull, or have a lock. without a pic its hard to say how to deal with it.
best is to run a separate circuit if possible using the proper fuse, wire and switching control.

 

Sounds about right.

 

Please be civil with each other, this is a forum to help, not to get into arguments.

 

I have been told by a mechanic/friend that I should try and change out what is shown in the manual as the "27 ST 30 A STARTER MTR" fuse/relay on my 2011 GX 460. I have found the replacement, and while I have been able to change out different fuses and a relay previously, this particular one is described as a "Type B" fuse in the owner's manual and instead of instructions on how to change out the fuse, the manual merely notes that I should contact the dealer. I would prefer not to.

This thread is as close as I have found, but the thread went sideways. Any chance someone can explain how I can remove/replace this particular, or any "Type B" fuse?

Much appreciated!