graham_mitchell

I got around to replacing my OBC light bulb today. The existing 'how to's were very helpful and left no surprises - thanks to all who contributed. The only information missing from every thread on the subject is the part number of the bulb! This info is not in PET, so here it is:

964.641.920.00



Nice to have the OBC display back!

fbfisher

Thanks Grahm, I need this now too. Where did you find the best description of how to replace the bulb? I need the DIY instructions for this. How many bulbs are needed? A post on the 964 board says two, but maybe that changed in the 993?

Davies

Would love some more info. I've been told many times that it's easier to replace the whole tach than go in and replace the OBC bulb...Can it really be that difficult?

mgianzero

Replacing the OBC bulb is really not that difficult. There are only two types of bulbs in the 993 VDO gauges. All the instrument warning lights/indicator lights use a .9W 12 V bulb. This is the same bulb used in the OBC. The background lighting for all the gauges uses a 1.5W 12V bulb. I am not sure which part number is for which bulb as I am not at home at this time to look it up.

The DIY from Robin's site explains the process reasonably well. There is only one bulb for the OBC, not two.

PM or email me if you still need help.

Marc

fbfisher

[QUOTE=graham_mitchell]I...The only information missing from every thread on the subject is the part number of the bulb! This info is not in PET, so here it is:

964.641.920.00



QUOTE]

mgianzero

One important point. Disconnect your battery FIRST, before unplugging your airbag. If you do not, the air bag is NOT at risk for falsely deploying. However, it will register a airbag fault code at start up which must be reset by a dealer or anyone with a PST-2 or equivalent system.

The airbag system will still perform correctly, but a warning light will remain on and can be rather annoying to look at the "!" everytime you start your car.

fbfisher

Graham, you have a PM.

graham_mitchell

fbfisher, I got the PM. It was 1.5 years ago now, so my memory is not that fresh. The job was fiddly but definitely DIYable. Iirc, remove the airbag first. It is connected by screws which are on the backside of the steering wheel. Reaching these can be fiddly. Be careful of the cable connecting the airbag to the steering wheel. Just take your time and be gentle when you pull this apart. You will need to remove the steering wheel. Try and work out a system of getting the wheel back on later in the exact same position on the spindle so that the steering wheel will still be level when the car wheels are straight. Once the steering wheel is off, the guages are easily removed by prying them with a screw driver but cover it in soft cloth to prevent damage. Also protect the neighbouring gauge which you will use as a pivot point. I can't remember the exact procedure of replacing the bulb so I assume that was very straightforward.

As I said my memory is vague so I may not have it 100% right, but I hope this helps.

fbfisher

Thanks for the reply. I DON'T WANT TO REMOVE MY SW

mgianzero

The recommended DIY above is pretty straight forward. The two screws behind the steering wheel that hold the air bag require a T-30 torx wrench. I purchased one from Sears that was roughly two inches long, just the right length to get back there, but not too long to interfere with the dash. You may need to apply some real torque (or apply a wrench) to initially break these screws loose as they are quite tight. You don't need to retighten them that tight when reinstalling them.

I have heard that most people remove their gauges by prying their edges. I found it much easier (and simplier) to push the gauges from behind. If you remove the plastic cover at the top of the luggage compartment (don't know what this piece is called) you can shine a flashlight into the back of your dash and locate the back to either the tachometer or the fuel gauge. Simply find a broomstick about 2 feet long and guide it through and to an open spot on the back of the gauge and give it a push (not with a hammer but your hands) and you will find the gauge pops right out. I find this approach to be less damaging and really quite easy to perform.