Porsche 911UK Forum

Welcome to the @Porsche911UK website. Register a free account today to become a member! Sign up is quick and easy, then you can view, participate in topics and posts across the site that covers all things Porsche.

Already registered and looking to recovery your account, select 'login in' and then the 'forget your password' option.

Under bonnet courtesy light

A993LAD

Well-known member
Joined
20 Mar 2007
Messages
721
Im trying to trace a parasitic current draw on my battery which has suddenly started running down quickly if I leave the car parked for a few days .

I'm starting by testing the battery drain under the bonnet but just realised there is an under bonnet courtesy light which might be drawing current so I need to make sure it is switched off whilst I've got the Bonnet open .

But stupidly I can't find the switch anywhere. does anybody know where it is Please?
 
Just click the latch over to the closed position using a screwdriver or similar.
 
Are you sure your battery is not on the way out especially if you have to turn off the light when the bonnet is open?

If the problem is irregular use of the car then I can recommend the battery isolator sold everywhere which is fitted to the negative terminal and consists of a wheel which you give a quick turn if and it isolated the battery. It can be fitted in minutes and is sold as an anti theft device.

Remember that unless your car is parked somewhere secure it also isolates the alarm unless you install the fused link which gives a trickle of power to the car.... thereby rendering the whole purpose redundant.
 
under bonnet curtesy light

i take the bulb out .its only for the fuse box . I carry one of them cheap wind up torches in case of emergencies
 
The most probable cause for excessive current drain is failing door switches. These does not only activate the interior lights, but a relay or two as well as the alarm/door lock control module. Turning off the interior lights masks this problem.

Another common problem is a failing on/off transistor in the Climate Control Module. This can leave the unit on. (it is supposed to shut off in 20 minutes after ignition off) However, this is normally about 500mA due to the CCU fan. However, if the fan has failed you could get about 100mA. Pull Fuse 1 to test.
The tachometer OBC LCD backlight circuit can fail to shut off when car is locked, this is also a probable cause for this current rating. Fuse 12.

Be sure to measure the current with all interior/bonnet/engine lights off, lock the doors, and wait for the CCU to turn off. The light switch in the luggage and engine compartments are placed in the lock mechanism. Depresss the latch to switch off the light.
You might consider opening the windows first to avoid having problems getting in due to a problem with immobilizer or similar.
Normal current draw at ignition off is normally around 20-25mA. Depending on aftermarket equipment installed, (alarms/stereos etc) this can increase to 30-40mA.

Cheers,
Tore
 
As Kerb-Scraper suggested - just flick the catch when the bonnet is open, and pop a rag in it so you don't forget to release it.
However, I'm wondering if you actually meant "whilst I've got the Bonnet closed...."
If this is the case, you can tell when you lock the car, as the alarm will report a fault when you lock it, by flashing the door LED's twice per second instead of once per second if one of the interior, bonnet or engine lid light is still lit.
 
Interesting post as I recently had the same issue.

I even went as far as to remove my speedo to see if the light is actually going out (which it wasn't!!). Even though it did go out when I used a screwdriver to fake the bonnet closing (I tried it numerous times as I couldn't see why it wasn't working)

Solution (as already suggested) : remove the bulb :)

Todd
 
As ToreB says

"Another common problem is a failing on/off transistor in the Climate Control Module. This can leave the unit on. (it is supposed to shut off in 20 minutes after ignition off) However, this is normally about 500mA due to the CCU fan. However, if the fan has failed you could get about 100mA. Pull Fuse 1 to test.
The tachometer OBC LCD backlight circuit can fail to shut off when car is locked, this is also a probable cause for this current rating. Fuse 12."


This is what happened to mine.

ATB
Bruce
 
As Tore said door switches were my problem a few years ago the alarm would also trigger at most inconvenient times.
 
toddgibbs123 said:
Interesting post as I recently had the same issue.

I even went as far as to remove my speedo to see if the light is actually going out (which it wasn't!!). Even though it did go out when I used a screwdriver to fake the bonnet closing (I tried it numerous times as I couldn't see why it wasn't working)

Solution (as already suggested) : remove the bulb :)

Todd

With the greatest respect; that's not a solution it's a bodge.

Possibly a faulty door switch is finding earth through the frunk light circuit. The illuminati do not take kindly to anything other than 100% functionality of all systems.
 
You are 100% right Kerb_scraper - I should have said "short-term fix until you are dedicate time to it". :)

Todd
 
toddgibbs123 said:
Interesting post as I recently had the same issue.

I even went as far as to remove my speedo to see if the light is actually going out (which it wasn't!!). Even though it did go out when I used a screwdriver to fake the bonnet closing (I tried it numerous times as I couldn't see why it wasn't working)

Solution (as already suggested) : remove the bulb :)

Todd


took speedo out? just leave phone on video in the frunk, then play it back.
 
timm996 said:
took speedo out? just leave phone on video in the frunk, then play it back.

Love it - its little ideas like this that make forums worthwhile :)
 

New Threads

Forum statistics

Threads
124,350
Messages
1,439,414
Members
48,706
Latest member
SBSEA
Back
Top