I purchased my ls460 about 4 months ago and recently it hasn't been starting or even turning over(well at times, if it sits a few days every now and then itll start perfectly fine). Like there's power from the battery going to the starter. The battery's fairly new same with the alternator and starter. I'm just confused as to why at times literally nothing happens. Hopefully someone has been through this before and it's something simple as a relay or fuse or possibly a bad connection somewhere.

 

It could be the starter relay.

 

Is the light on the start/stop button green when you try to start it?

 

yes everytime I depress the brake pedal. I also thought maybe the key batteries were dying. But it illuminates from orange to green when I press the pedal

 

I was honestly searching for one last night but autozone says they're out of stock. I honestly don't want to purchase one off Amazon.

 

Might be a good idea to start with checking the battery connections for corrosion and then a load test before buying anything.

 

What sort of starting sequence.are you using. Orange to green? Are you going to the ACC power on before you press the brake pedal? Not sure what that would do. The correct sequence is to just depress and hold the brake pedal and then press and release the START button.

 

no I just get in depress the brake and press button and the wheel comes out and set but At times it doesn't turnover. But at times it does. I purchased new relays and fuses that I'm going to replace once I'm home from the road.

 

purchased a load tester I'm gonna test once I'm home also purchase starter relay, ignition relay and fuses. Fingers crossed hope it works and everythings well from there. By any chance do you know if theres any diagrams for all ground wires that connects to chasis or block?

 

I don't have any schematics for my car because I worked for Toyota dealers most of my adult life and on any model the main grounds will be in and around the battery/engine/bellhousing area unless it's a hybrid, there are chassis grounds all over the car for different systems but you don't have to worry about those.
You would only be interested in the ground on the battery and you can easily test that with a multimeter...resistance should be very low like 1- 1.4 ohm or so testing with the negative lead of the multimeter on the negative cable and the other lead on the head or block etc. You don't have to disconnect the battery terminal to do this just don't start poking wires indiscriminately or test batt voltage without switching to dc volts.

Because you said the alternator and starter have been changed probably means someone else was chasing this problem so who knows....people always say the battery is good but unless you have it load tested and know what the voltage dropped to while cranking it's just a guess, also people who drive to an auto store to have it tested have charged the battery abit while driving there.
I still use a carbon pile load tester because I like to see the amps as well as the volts and I think the newer ones are just doing a cell voltage comparison .
If you get a chance when it won't start again, try starting it with a boost and if it starts...

The negative cable runs from your battery under the batt box and has a chassis connection in that area and should continue to the bell housing/starter bolt but I haven't seen that because I haven't had any problems yet so that's a semi educated guess. There is a large chassis ground on the passenger side front of the engine, it runs from the front of the timing cover to the circled bolt in the picture below so being the alt was changed I would have a look at that too just in case.

From that nut in the picture the ground goes down and runs toward the drivers side.

 

so there's 2 main grounds the one from the battery and the one on the front side of the engine near the serpentine belt? I purchased a load tester a while ago ive been on the road the past 3 months but ill be home this weekend and ill attempt. I also purchased new relays for ignition, starter and new relays just incase as well. Ill give it a shot over the weekend and see what I get and give an update once ive completed my semi professional diag. Worst case I'll grab sand paper and clean the grounds as well just to make sure they're making solid connections and also check to make sure neither are loose. I appreciate the response very much. Also I worked at toyota for a few months as well a few years back and became ase certified through pepboys so I have a little knowledge still learning. It's a little bit more strenuous than honda lol what I use to drive before getting my ls460 lol