Boxster 2.5 MY1999 - electrics

[britairdog]

My car is a UK spec 2.5 Boxster MY1999. After a major accident repair, the internal ( overhead) light does not work at all, either in auto or manual mode. I have checked the bulb is ok!! The footwell lights fitted in the lower door panel are also inoperative. As a possible indicator of the problem, the central locking system does not re-arm if the car is not entered within 30 seconds of disarming the system, otherwise it is ok.

Porsche think that the alarm and control unit under the passenger seat is faulty and that the cost to fix is $800USD (500 Sterling pounds) I think that it could be a simple wiring fault due to the repair.

Any ideas out there? Can anyone supply a suitable wiring diagram?

[Loren]

Inside lights, alarm, and power windows are all on the same circuit. Have you checked to see that there is a good 15 A fuse in C3 (Third row down, third fuse from the left). And all of those do go through the alarm unit so... they could be right.

[0586slb]

I'm surprised think the control unit is faulty straight away, as the re-lock option is configurable with the PST2 for on/off, how many seconds to re-lock etc.

Having looked at the wiring diagram, the interior lights are powered in the following way:

The positive comes from Bus Bar 7, 'Consumer Switched Off' which stays live for about 10 if alarm off, engine off. If car locked and alarm active, BB7 is switched off. Individual components have the negative (earth) side switched to control the individual device. Other things supplied from BB7 are:

Luggage compartment light Front

Luggage compartment light Rear

Make-Up mirror Left

Make-Up mirror Right

Seat Memory.

Are any of these working?

BB7 is switched from the alarm control unit. Has the plug been disturbed? Look at pin II/4 and II/8 on the alarm CU. OK?

Finally, fuse C3 (15A) is worth a check.

[0586slb]

Sorry Loren, busy with my long reply as you replied with the fuse C3 info!

Chris

[britairdog]

I'm surprised think the control unit is faulty straight away, as the re-lock option is configurable with the PST2 for on/off, how many seconds to re-lock etc.

Having looked at the wiring diagram, the interior lights are powered in the following way:

The positive comes from Bus Bar 7, 'Consumer Switched Off' which stays live for about 10 if alarm off, engine off. If car locked and alarm active, BB7 is switched off. Individual components have the negative (earth) side switched to control the individual device. Other things supplied from BB7 are:

Luggage compartment light Front

Luggage compartment light Rear

Make-Up mirror Left

Make-Up mirror Right

Seat Memory.

Are any of these working?

BB7 is switched from the alarm control unit. Has the plug been disturbed? Look at pin II/4 and II/8 on the alarm CU. OK?

Finally, fuse C3 (15A) is worth a check.

<{POST_SNAPBACK}>

Thank you for the advice on this problem. I checked out all suggested fixes, but nothing cured the fault. It turned out that Porsche tech department were right - the only answer was to replace the alarm module ( under the passenger seat) . This took 2 hours and £400 (£700 USD) from my bank account, just to get the interior lights working!! My current car is now sold to a new owner on 20 June, my new 987 Boxster S arrives next day........