momogala

Hey guys… so today my rx450h is dead. No lights on nothing. Trunk will not open. I tried to jump from the engine bay and no dice. I crawled into the trunk and got to the main battery and hooked it up to a charger and no dice. I got the lights to come on but not enough juice to start the car. How do I open the trunk with the truck dead? I need to replace the 12v battery. Please help. Thanks

Clutchless

You should be able to push the switch hidden on the center of the back hatch and pull it up manually. Make sure the valet security button in the glove box is in the correct position for it to open.


See this
https://www.clublexus.com/forums/rx-...pen-trunk.html

salimshah

What happened when you hooked up the charger? 450H draws substantially less current from 12v battery to start as the actual start is done by the traction battery. This the reason why the jump terminals are so small in the engine bay.

So next time when you charge or connect jumper cables, check the voltage.If you still experience trouble we will try you to guide you.

Not to strike any fear, but please try get your 450 running [at least once a week].

Salim

momogala

So when we tried to use a jump box to jump it, the lights came on in the car and headlights but car would not turn over. Once we removed the jump box, all lights immediately went off. We use the car daily.

703

You can open the trunk without power. It’s on the owners manual.

salimshah

So the instrument cluster came alive. Any error message in the display or you get "Ready" light. Being hybrid the engine need not come on.

In either case, your 12v battery is no good. How old is it? Please read the 12v battery thread in the 450RX sub-forum.

Salim
The traction battery, which starts the ICE needs to retain charge and it gets charged with the ICE and energy recovery. If you do not use the car, more so now that it is disabled, please make every effort to get it going else you will be facing lot of aggravation as the jump of the traction battery is a dealer/specialized shop option and the RX may have to be towed.

momogala

Ive read the entire thing. I can’t find what to do to get into the trunk to change the battery if the car is dead. Some say there is a key hole by the license plate. Some say turn the key twice in the driver door. Some say there is a emergency latch inside the car. But nothing concrete. Looking for some advice

salimshah

page 70 of owners manual describes the process. Just fold down the rear seats and climb in from the cabin. Open/remove small cover near center bottom of the tail gate.

https://drivers.lexus.com/lexusdrive...anuals?type=om

Are we going in circles here? I thought you could jumper cable in the engine compartment [fuse box in the engine] and restore power ... with that you can release the hatch from outside [above the license plate, key fob, by the driver with (above left knee ... assuming the button in glove compartment is enabled].

Salim

ps: Based on your RX options there are two different ways to open, Best is to see the owner's manual. Good luck finding the proper battery. It is not going to be cheap .... but the thing lasts a long time ... you would have gone through 2 or 3 replacement in non-hybrid.

zmel

Make sure all doors unlocked, then you should be able to open the back door manually as shown

703

Manual release inside the car with a screw driver. That is the only way.

I have done this before.

momogala

Hey guys. Ok so we used a heavy duty jump box this time and hooked up to the front and boosted the car. Got it started and opened the trunk and changed the battery. Thank u all

salimshah

So happy that things worked out for you.

When the 12v battery stops keeping up the charge, you need nominal boost for hybrid [once you turn off the auto light and not step on brakes .... just to get minimal loading]. In this condition, you should be able to operate door lock/unlock.

My guess is your old battery lost a cell or two and it was clamping the smaller boost and that would have prevented getting the system up.

Salim

MellonC00

How many miles did you have on your car and how old?

Gmere

but the car manual is locked in the the car

salimshah

How many people enter the RX through the trunk?

I do get the joke.

Other alternatives are:
Look up the owners' manual on line.
Call local Lexus dealership for ideas/suggestions. [I have witnessed how hard the folks are Lexus of Austin try to help customers]

Salim