Hi Folks,

Looking to get some guidance on Jump Starting my 2023 RX350H. I am familiar with the connection points under the hood, and that the negative cable needs to go to the other side of the engine.
My problem as you might suspect, is cables that are too short on my portable jumpers (I have two, and both are too short).

I don't have much car knowledge but reading up enough made it clear that picking a random bolt under the hood near the positive terminal can fry the ECU, which is why I am hoping someone can give me a picture showing which (if any) connection point under the hood on the driver side is safe for use as the negative terminal.
I don't want to crawl through the car again to open the trunk, to get direct access to the battery or drop another 100 bucks on another jumper with longer cables.

I have the Gooloo jumpers btw and they have a proprietary connector so I can't even get longer cables without modifying the cables which I have neither the tools or skills to do.

Any help would be greatly appreciated, thanks.


Update 1:
Video showing some points NOT to use: Image of the under the hood (image from google, but matches mine exactly) (Not sure why upload is not working, so here is the link)
https://www.lexusofakron-canton.com/...dth=400%20400w

I also have the Goloo jumper in my 2025 RX350h for emergency and I wouldn’t have known how to jump my car as well if I ever needed to.

thanks in advance

I just re-watched a short video (YT) posted by a Lexus dealer. They all say the same thing which is positive clamp to the jump post, negative clamp to a bare bolt on the engine (the screenshots are of an RX350h video).

I used a single 'traditional' jumper cable connected to the recommended ground point when starting. Wrap the exposed alligator clips in a towel if you are worried about an accidental too-close connection.

Also consider this: If your battery is totally 'flat' (discharged) your Jumper will require a 'boost mode'. The one we had didn't have this so we needed to wait for the AAA guy that the dealer sent. I needed to direct him to connect to the right-side connector, he didn't know.

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BTW, an auto electric shop should be able to splice & lengthen your Gooloo cable, if you want to take that action.

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It is good to familiarize yourself with the procedure for entering the car with a flat battery...

An important difference in jumping a Lexus/Toyota hybrid from all the traditional jump starts we have performed on conventional infernal combustion engines is that it is not the 12 volt battery energizing the starter motor as before. The 288 volt traction battery energizes the MG1 (motor generator one) which is attached to the IC engine. All the 12 volt battery does is stabilize the voltage for the lights, radio, seat and window heaters and, oh yes, the relay to engage the MG1 to spin.
All said, the amperage needed is far less than the 100+ amps we used to fear use to crank the starter. Our hybrids don't have starters or alternators.

This doesn't help the OP, but for those that havent already bought a jump starter, the Schumacher SL1648 has leads that reach the Lexus approved jump points.

There is also the option of the permanently installed Ionic Emergency Start which is a Bluetooth enabled jump starter that can be enabled from a phone app, taking all the hassle out of jump starting the RX.

My understanding is you just connect the jumpers under the hood like above to open up the back hatch & then charge the actual battery that is under the floor so as not to fry any electronics.

Anytime one hooks up a jumper incorrectly, one risks damaging sensitive electrical equipment. The moment the jump pack is hooked up, there will be a large inrush of current to the dead battery. The current to start the vehicle is low by comparison.

Thank you for sharing, I will definitely look into the Auto shop thing. I am familiar with how to open the door on a dead battery, and then get to the trunk to the actual battery but doing that from inside the car can be a bit difficult.
Side note, any idea what the Gauge of the cables should be on Gooloo GT4000? Google offers confusing information.
On one hand it says 8 AWG is fine, but this is technically supposed to be a 4000A jump starter, and you would need much higher Gauge (4/0 possibly) cables for that.
Am I correct in assuming 8 AWG is fine since its just a short burst of usage?


Technically yes, that's what its meant for and what all the videos seem to say too. The manual I read seemed to not mention jump starting the battery in the back which leads me to believe that you can jump start from under the hood too, but even if not just the convenience of getting the trunk open is worth the hassle.

I updated my post to include an image of under the hood (not my car, got it off the internet but exact match) and not much places to connect and a video of a person who is showing some Lexus docs saying explicitly which points not to use. Doesn't leave much room for other options.
As far as I see most other stuff is painted black. I was at the dealership today (got the battery replaced under warranty) and one person there said the painted latch could work......

The owner's manual procedure calls for another vehicle and jumper cables, but using a booster is similar. It just calls for attaching the jumper cables to the underhood jump points and starting the hybrid system with those points still attached. It does not call for opening the trunk and jumping from there. The two times I jump started ours, with a booster, thats how I did it. I then charged the battery from the same points, and I have charged it that way many times since.

Hence the pics I posted. That Dealer is showing that you can clamp your negative cable to another unpainted point, in this case it's a bolt on the nearer side of the engine.

That's the problem I am trying to solve. My cables don't reach that bold point that Lexus recommends.

Sorry, the pic I sent is the Dealer showing the bolt on the closer side of the engine, near the fuse box with the positive tab, it's probably 30" from the fuse box. How short are your cables??

Sorry, I didn't even realize you had uploaded any image until you pointed it out. I was on VPN, and the image wasn't showing up, not even as a broken icon so I didn't even know the image was there.

And also, THANK YOU so much. I just went to my car and verified, that the cables easily reach between this bolt and the positive terminal. (16 inch cables Gooloo GT4000 btw)

I took a higher res pic to wrap this thread up. For those "who come after"

Update:
It seems like its not a VPN issue. Pictures don't load for me randomly. Can anyone confirm they can see the two images that are in this post? I can't see my own images unless I go into edit post.

OK, good to hear it! Weird about the pics, but weirder things have happened with digital stuff!