Hello! Yesterday after doing some errands in my 1999 automatic A4 I spent a few minutes at home before needing to go back out in the car. However, as I tried to start it, it was completely dead. No lights, no radio, no dash lights, nothing. I can't even lock the doors. I tried jump starting the car and nothing. The battery has 12.4 volts. None of the fuses are out on the main fuse box or under the dash. I don't have a VagCom. Any ideas?

 

Sounds like the car is not cranking at all?

Not enough detail yet but if you can get your hands on a new or known good battery, you could see if it would start with that. It's possible your alternator is no longer putting out enough charge to keep the battery charged and the battery drained to a very low voltage.

If you have a multi-meter, check the voltage on the battery to see if it is charged up. If you don't have one, it is useful and they usually have basic ones at the local parts store.

If you can't get your hands on a new or known good battery, take it to a local parts store and they can test the battery for you and possibly charge it back up. Then you would know that the battery is good and you can turn your attention to the rest of the charging system like the alternator and ignition coil.

Good luck, I know if can be frustrating when you can't get the car to start.

 

Thanks so much for your response. There are 12.4 volts across the battery with my multimeter. As I wrote I tried jumping it with another car--nothing, no lights, nothing electrical. So, no way will it even turn over. I think it must be a short somewhere. I can't find anything from the postive terminal to through the firewall to the first junction box in the cabin (however I haven't lifted the computer box to look under it). I haven't checked the ground cable yet either.

 

A common failure for the B5 A4 is the ignition switch. If this switch goes bad (and when it does it's often intermittent), it needs to be replaced. The part itself is not too expensive and can be a DIY project.

 

OK. I'll search for instrucitons on checking the ignition switch.

Would this however cause the whole electrical system to be out? I don't have headlights, dash lights; I can't lock the doors, etc.

Thanks,
Rus

 

Hmm it shouldn't have an impact on the car's entire electrical system, only those things that operate when the key is turned to the ON position.

 

I say you use your multi-meter to go step by step through the electrical system. While wiring diagrams are intimidating at first, in time they start making sense.

Here is also an article on how to get started with troubleshooting electrical systems in cars.
How to Diagnose Car Electrical Problems by Tracing Voltage Drops

While the ignition switch could be the problem, power should still be getting to the ignition switch and really to most of the points in the fuse box. Have you found the fuse box at the left of the dash yet? If so, there are multiple points there which should be getting 12Vs if the battery is connected. Be careful what you poke at but start by measuring across a fuse at the top of the fuse. If nothing then you will need to go step by step from the battery to see where the power is getting to and where it stops going.

Here is a high level summary diagram I found which claims to be from a B5 A4:


source: Audi A4 B5 Wiring Diagram - Guide And Manual

If you have access to a Bentley manual, that will give you more detail but this might help get you started towards tracing the power back to the fuse box. As you will see, most of the power connections lead there and power should be getting to the fusebox unless the main connections on the battery are not making a good connection. Make sure they are clean and on securely - especially if your are not seeing power right after the main battery connection.

Good luck with the next step and getting oriented.

 

Hi,

Thank you so much for all your work! I think I can solve this problem now. I really appreciate what you've done.

Rus

 

What was problem in end

 

By the way - if I remember correctly the ignition switch was a recall item at one time (for the 1997 year model). Not sure if it still applies to the 1999 model year or since the car is so old, but it may be worth a call to save a few bucks just in case.