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Bonnet Release DIY - for when the battery dies

GT4

Well-known member
Joined
8 Nov 2008
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30,181
The Boxster, Cayman, 996 and 997 are all designed with a battery stored under the front bonnet.

This is great for weight distribution, not so great when the said battery dies and locks itself in.

There are 5 basic entry methods. Three electrical and two mechanical.

Early Boxster and 996 models have cable operated releases, activated by levers by the driver's seat. Later models and all Cayman and 997 have buttons by the driver's seat to operate the locks by electronic solenoid.

The early models have the levers locked out when the car is locked and the button versions are isolated when the car is locked.

If yours is a Button Model zip straight to the last entry of this post. On the way note the pain you have avoided by having a later model!

LEVER MODELS

You have four options with the mechanical lever models: access the cables internally or externally or energise the unlock relay circuits via engine bay or fuse box.

External Cable access (Designed by Porsche if keys, battery absent etc)

There are two external cable release "eyes" - one at each end of the car.

NOTE: Lever release cables are routed to the Passenger side (front and real) (RHD).
Electronic Release models also have these cables, but the front cable is routed to the Driver's side (RHD).


Front Release
front_bonnet_release_116_582.jpg

emergency_cable_elec_releases_1_164_183.jpg

emergency_cable_elec_releases_2_482_108.jpg

emergency_cable_elec_releases_3_139_117.jpg

emergency_cable_elec_releases_4_124_649.jpg


Access this "eye" via removal of the wheel arch liner. Remove from the Passenger's side (Lever Model) (RHD).

The centre pin plastic rivets for the liner just prize out (pull up centre pin with long nosed pliers/screwdriver and they "shrink" to release).

Look a bit like this:
fix111.jpg


The problem with this method is that a previous "helpful" owner may have moved the cable to somewhere more accessible (which you don't know) or it has been dislodged by repair work.

Rear Release:
rear_deck_release_196_153.jpg


Inside the engine bay there is a +ve jump start and charging point. This can be accessed via the rear cable release. Simply slide in a plastic ruler or hook to fish out the cable lying under the Passenger's side (RHD) rear lamp cluster. You can energise the car via this terminal and an unpainted earth.

0608_ec_23z2000_porsche_996underhood_engine_195.jpg

rear_release_cable_393_144.jpg


Internal Cable Access

It is only the levers that are locked out by the dead battery, so the aim of this method is to overide the locking plate or pull the release cable directly.

Locking Plate Overide
If you carefully "pick" the release locking plate down the gap between the levers with a long thin screwdriver you can release the cable locking mechanism. Now you can pull the lever.

Cable Pull
Carefully prize open the lever assembly structure (by drivers door) and unscrew the three M5 Allen bolts and you can manually pull the release cable with a pair of pliers or hook (it is the levers that are locked, the cable is free to move).

Unscrew the panel on the right of the driver that houses the bonnet release. They need loosening and the whole housing should lift out. Don't take the Allen bolts out all the way otherwise they are a real pain to get back in!

Once you have moved the housing a little (you don't need to remove it completely), you should be able to pull the bonnet. You should see the deadbolt behind the lever which is preventing the lever from moving. Once the bonnet is open a bit of charge should allow you to unlock with the remote and disable to deadlock.

The Allen bolts will be covered by some plastic caps. Just lever them off (there are 3 of them) and the allen bolts are beneath. Once you've loosened these the plastic plate will lift off enough to bypass the deadlock and the bonnet will open

Tedwedz Cable Pull

Anyway solved the problem by pulling the cable from by the fuse box! You just yank the whole cable! Anyway pulling the cable by the drivers door floor works, between bonnet and floor handle

p1070727s_718_158.jpg



Energise the locks with a "Fuse Buddy"

The Lever Models don't have a "Red Terminal", so make your own!

buss_fuse_tap_521.jpg


jumper_214.jpg


Connect both spades of a dummy fuse into position C3 with 12v positive and connect the negative to an exposed part of the body (ie not painted) - you should be able to use the door catch hoop on the rear of the door frame.

You can use a jump-pack or set of jump leads to another car battery for example. (connect the negative of the donor battery last in case of sparks etc)

Make one yourself using a spare fuse (solder on to both spades) - the lump of pig iron on the end is so your 12v crocs can actually hold it!

There is an OPC TSB (Porsche Technical Service Bulletin) if bonnets lock (and the techies cant be bothered to reach around for possibly displaced cables etc)

Front and Rear Hood Release Inoperative [grp5 1/96 5510 1/21/97] 1pg

Should the front and rear hood releases become inoperative due to a disconnected or discharged battery, the following procedure will allow the hoods to be operated electrically under these conditions.

Open the driver's door.
Using an external battery, connect the negative lead to the door stop.
Connect the positive lead to both sides of fuse "C3".
With the door open, move the door latch with a screwdriver into the closed position.
Using the key, lock and unlock the door.
The front and rear hood releases can now be operated.
Note: If the vehicle is in the workshop and the battery must be disconnected, try to park the vehicle in a safe area where it is not necessary to latch the front hood.

The TSB also suggests fitting an inline 30 amp fuse (if you dont use a "buddy" with built in fuse carrier).


BUTTON MODELS

This is the easier solution (that's why Porsche evolved it!)

Just pull the red +ve terminal out of the fuse box and attach the positive of a 12v battery.

Connect the negative to an exposed part of the body (ie not painted) - you should be able to use the door catch hoop on the rear of the door frame.

You can use a jump-pack or set of jump leads to another car battery for example. (connect the negative of the donor battery last in case of sparks etc)

Now you have energised your car you can open the bonnet (or run anything else in theory).

jump_starting_996_2_454.jpg

jump_starting_996_3_548.jpg

jump_starting_996_4_234.jpg

jump_starting_996_5_896.jpg

jump_starting_996_6_168.jpg

jump_starting_996_7_389.jpg

jump_starting_996_8_158.jpg


With thanks to RichardH, TBrown, Tedwedz et al.
 
IMPORTANT NOTE FOR 996.2 OWNERS.

Don't pull the red plastic block out as far as I did!

Pulling it by hand should bring it out half way which is all you need to do. If you use pliers this might happen!

996batteryterminalfuse003.jpg


That pink wire was connected to the red connector block and needs to be for the process to work.
 
... or any (late) 996.1 with button (not lever) releases.

All button release get the red terminal.
 
Hi,
Great info, thank you for this. I have a battery charger and a 2004 996 (button release), can I use this to get enough power to pop the bonnet open?
 
Possibly, depends on the current provided.

Do you not have a spare 12v battery (in a car or on its own) and jump leads?
 
Is it possible to charge the battery through the fag lighter :?:
 
Waz 911 said:
Is it possible to charge the battery through the fag lighter :?:

Short answer: yes.

Longer answer: 996.2 - yes, 996.1 - only if the cigar lighter socket is rewired permanent live (default is ignition live).
 
Thanks again to GT4 for helping out with this - FWIW i spent a lot of time messing about with a fusebuddy that was for some reason unsuccessful, the easiest option on my 996.1 was to prise open the carpet next to the fuse box (just wedged a screwdriver in between the rubber seal and carpet, it took a couple of good yanks on the cable).
 
Apologies to those with newly impaired hearing, forgot to add the advice for disconnecting batteries (which applies here too):


To change the battery:

Put the key in the ignition and turn to "1".

That way you won't be deafened by the alarm module (cunningly placed by the battery, under the front bonnet which is also perfectly designed to channel all that siren goodness to your ear drums).

Disconnect negative first.

Swap batteries

Reconnect negative last.

Don't forget to reconnect the acid vapour overflow pipe.


The important bit here is the key in ignition "1".
 
Hello

I followed the method of the positive in the fuse box and the door striker, unfortunately the horn sounded but neither hood or engine lid switches activated to open. The fron t cable pull broke when I tried to open it!

Before I sell the car as an anchor any other ideas on how to open either lid?

Alisdair
 
S2000 said:
Hello

I followed the method of the positive in the fuse box and the door striker, unfortunately the horn sounded but neither hood or engine lid switches activated to open. The fron t cable pull broke when I tried to open it!

Before I sell the car as an anchor any other ideas on how to open either lid?

Alisdair

The driver's manual states:

1. Use the key to unlock the vehicle at the door lock. Leave the key in the door lock.

It later says;

Note. If the vehicle was locked, the alarm horn will sound when the neagtive cable is connected.

When you unlocked the car did you leave the key in the door lock :?:
 
Thanks for your reply, I left the key in the door after unllockig, but none of the release buttons would work.
 

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