Best Way To Open Car When The 12V Battery Is Dead?

More commonly I've seen, not insulation on one jaw (which would be kind of weird), but shiny copper teeth in both jaws, only where if you look closely, only on one side are the teeth connected to the cable.

That has to be the side in contact with the metal tab in the fusebox.

But there are lots of threads about electrical jumping of a Prius. What this thread's about is the OP's driver door, where the mechanical key doesn't mechanically unlock the door. It's been a couple weeks with no updates from the OP on that issue.

 

I haven't had the need to work on the locks in our '13 V wagon, so I don't have any first-hand experience with the locks on this car, but I have some experience with locks and actuators on other vehicles. You say the dealer replaced the "locks" under warranty. Was it the actuators or the key cylinders?
If it was the actuators, it could be possible they put the wrong actuator in the driver's door. Many times the driver's door is the "master" actuator that all the others follow. For instance, there would be no provision for a key-unlock on a rear door actuator (or maybe not even on a passenger door actuator -- I'm not sure, and can't check our car because my wife has it at work)

Just a thought.

 

I realize that jumper cables often only run the wire to one side of the jaw. My big cables won't make any contact with the little tab, but our other set (bought specifically for Prius) will fit, although you still need to check to make sure the jaw on the tab is touching on the "wire" side. To make life even easier for next time, I bought a small lithium booster/jumper pack that has nice small jaws AND are build so both sides of the jaw are connected to the wire.

 

The Prius v has an air vent duct near the 12v battery that goes out and under the rear of the car. The vent should stay closed unless air is vented out. You can think about wiring a charger cable (with a diode to prevent shorts). The problem is the vent ducts may stay open permanently and that could allow bugs and dust from the outside going in.



As for me I installed a charger port inside the right light cover door.

 

Actually some chargers won't charge if there is no voltage because it's blocked by the diode. So a diode may not work for some chargers. Alternative is to just keep the cable cover sealed and waterproof.

 

Just looking at this fresh...

why not

1. open the driver's door with the mechanical key,
2. connect a "memory retainer" to the OBDII socket (providing 12v power)
3. use the power to open the liftgate the normal way

Seems like a good off-label use for a cheap memory saver tool.

 

The op claimed the mechanical key did not work without power which is normally not true. But in his case the mechanical linkage or the cut of the key may have been bad. For the rest of us who have tried the key ahead of time, a normal jump or jump box at the fuse box would work if the user knows it takes a couple tries to initiate the computers.

 

Concur with all of this. Was gonna comment, then saw the intitial post was some time back. Was the mechanical key missing or something?? Didn't read the whole thread.

It might take more oomph than a 9 volt battery the cheapies use?

I have a Clore JNC660 jump pack (old school with a fairly skookum battery inside) which has a cig lighter socket. I plug a Clore Solar ESA30 memory saver cable between that and the OBD port. Something like that would work well.

One wrinkle for my setup though, if it was me with the dead battery: I've got the jump pack and memory saver cable stored in the tray under the hatch floor.

 

Not likely a memory saver would allow the hatch motor to operate to say nothing of initializing powered down cpus. A jump pack would work if the user realized the cpus require initiation time.

 

Well the $20 one from walmart looks like it can deliver at least a few amps, and it's going straight to B+... so even if it isn't enough juice to do the hatch-popping, it stands a chance of being accumulated in the 12v battery so you could try again later. The walmart offering terminates in a car lighter plug, and the kit includes a matching socket with spring clips that could go on a pretty good variety of batteries.

That ought to work nicely with most jump packs and loose batteries. Way more power than the 9v type.

 

The roadster has single point failure hood cable pull and trunk lid lock. Some rig an emergency cable loop front and rear to open each compartment. A front loop would work with the Prius to provide physical access to the under hood jump points. Likewise a rear loop for the trunk lid lock.

 

I know this is an older thread but it is the top result for googling "open 2009 prius dead battery" for some reason. This probably applies to the 2013 this thread was about as well.

My 2009 prius 12v battery died while the car was sitting.
Could not get it to unlock - the mechanical key in the fob would go in the slot and turn to the left but it would not open the door.

Following some advice I read elsewhere I did the following:
1. Put it in turn it by hand to the left then back to the right
2. Put a pair of needlenose pliers on the key for more leverage then turn it as far to the left as I could
3. Then back to the right *past* the point where it initially started

It seemed like turning the key to the right past where it started it what did the trick.
Door finally unlocked.

This is different than the sequence that unlocked it when the car had power, there I just turned the key to the left and held it there then the car unlocked. Just wanted to shore in case it might help anyone else.

 

^ From the initial post in this thread. I appreciate this is an old post, but just for the record, I don't believe it's the case, that the emergency key needs.power.

 

Agreed. The emergency key tucked into the fob is purely mechanical.

 

With power:
- I put the mechanical key in
- Turned it to the left
- Held it there for several seconds
- Hear the "doors unlocking" noise and the car unlocks.

With no power?
This did not work - no response from car, door stayed locked.

With no power, what worked was:
1. Grabbed the key with needlenose pliers
2. Turned it far left as possible
3. Turned it back far right as possible going slightly past the point where it starts
4. Then it unlocked

There might be an easier way to do this, but this was my experience and I thought it might be helpful to others.

 

You probably saw the car's reaction to seeing the normally-momentary "key is being turned left" signal maintained for an unexpectedly long period. It'll do the same thing if the sensors in the actuator fail and produce signals that don't make sense. It unlocks the car as a way of getting your attention that something isn't working right.

As you saw, turning the key right is the direction for mechanically unlocking. You would turn it left to mechanically lock. Neither requires power (though, of course, the other doors will follow suit only if there is power).

 

If the mechanical key DID require power, it wouldn’t be very useful.

 

Could be. It was an oddly long wait before it unlocked.

I found that trying to turn it to the right just using my hand did not work, I'm an average sized guy. Perhaps I simply don't have the hand strength to exert enough force on the tiny mechanical key?

Either way I thought my experience would be helpful to people in my same position. My suspicion is that you'll find most people do not have the leverage to get the mechanical key to open the car purely by trying to turn the tiny thing, which is why a lot of people try it and conclude it doesn't work when the car doesn't have power.

It's helpful to know it *can* work - if you get more leverage.

 

It could also be the condition of the locking mechanism. I've had to go the mechanical key unlocking route twice, and in neither instance did I find it difficult to turn the key in the lock to unlock the door. (I've never tried to lock it mechanically.)

 

Mine works pretty easily (both directions), but it's possible somebody has a mechanism that has rusted up some and would benefit from being worked back and forth a bunch of times, or even taken out and lubed.

Sometimes the "just add leverage" approach can be overused ... breaking the key off in there never made anybody's day.