97 a6 quattro wagon, every morning and somtimes during the day it wont start without a jump, it acts like the battery is dead, selinoid will click, click, click and somtimes shifting to nuetral it will start right up other times if I hook a booster to it it will start right up, sometimes just to wait a minute and come back it will start right up, and usually when it is jumped as it starts the sunroof opens and sometimes all the windows????? Spooky, replaced battery ( it was the original) to no avail. also during cold winter mornings , below 35 degrees f. it will crank to slow to start and eventually the battery will go dead, and then to hook my booster up to it it starts right up, what do you think starter? switch? wire problem? alternator? any ideas? thanks

 

I assume it starts ok unless it has been sitting for a while. (or only ran a short while.) if so,
I would suspect a "parasitic" drain. These cars are hard to troubleshoot for this as they have many features that draw on the battery when everything is off.

BUT before going down that path... do you know what the battery voltage is under the following conditions:

1. Battery charged and not connected (should be close to 12.5 volts)
2. Let it charge up and leave it not connected over night, then check it. (should be close to above)
3. Battery connected, everything off (should be close to above)
4. Engine running (should stabilize at just over 14v)
5. Let it charge up and leave it over night and check it. (Should be close to #3.)

NOTES:
1 & 2 check the battery itself.
3. Checks for large drains on the battery.
4. Checks your charging system.
5. Checks for small drains on the system.

To find drains on older cars, I would pull the fuses and check for voltage across the terminals. anytime there is a voltage difference, there will be current flowing in that circuit. In older cars, that isn't normal. But it is normal _sometimes_ with these.... Clear as mud?

OBTW: Corrosion on the battery cables, including where they connect to ground and the starter, can cause intermittent starting issues. I hope you have checked and cleaned these.

 

Check the ground between the motor and frame. It is on the passenger side front. You'll have to do it from the bottom.
Don't assume that it is OK if the connections are tight.

Remove the wire - clean all contact areas and put it back together.

 

Yes< I have checked and replaced the battery and redid the ground straps and checked the starter connections and gone through the fuse box and pulled every thing none essential drawing power but problem persists and it can happen anytime even if the car has just been driven, one problem I have dealing with this car is that I am told the battery must be hooked up or power supplied to the car constantly or the transmission servos will lose their memory and car will have to be taken to the dealer to reprogram, Is this true? so I am afraid to just yank everything apart . thanks for any help

 

I do not know about that.... I had mine disconnected for 4 months and didn't have to reprogram the transmission. It MIGHT have to relearn the shift points..... (A few rough shifts until it adjusts for the car.)

 

no.. that is NOT true...

 

I don't know if this applies to the 97 but a friend had a problem like yours with a 2003 Audi and the dealer finally found a bad door switch.