I have a 1991 525 i BMW, the battery was drained and went to jump start it. When i tried to start the car the horn started beeping, engine would turn over but wouldnt start. Was told in need to so a special sequence with the code button near the radio panel. Can you help with this?

Hi, chances are you have at least one bad battery cable. Check them with an ohm meter. If you have any resistance in your reading, say above 0.02 change your cable. Hope that helps.

this sounds like a low battery problem ... the horn and lights do not take much energy to turn on, but starting the engine takes a lot of power. Try jumping the Jeep with another car, or a battery jump pack (available at any auto-parts store). If the engine kicks over and starts, then leave your Jeep running in park for about 15 minutes. After 15 minutes of running, turn the Jeep off and then try to start it again with no jump -- if it starts, you had a low battery, but the issue is probably solved (running the engine recharges the battery). If, after you have had the car running for 15 minutes and turn it off, it does not start on its own, you probably need a new battery (and you should have your electrical system checked as you might have a bad alternator that is not charging your battery). Sears Auto Canter has a great piece of equipment that can test your battery, and your entire electrical system (including the alternator) in just a few minutes. I recommend that you take your Jeep to a Sears Auto Center and have it checked, whether or not the jump worked because their system can make sure that there is not a slow drain on the battery (due to a loose connection or something like that) which would cause you to have the same problem again.

It is likely your alternator has failed and the battery has drained. The car may jump start, but it will not go very far unless you charge the battery or replace the alternator. are you stranded somewhere?

it sounds like the vehicle is not recognizing the key that you are using try another key that is made for the vehicle

You need to check for any lighting left on overnight if not try to fully recharge your battery and perform a load test on it to see if it will hold the charge if so possible drainage off of interior lighting switches or alarm possible

Put a volt meter across the battery terminals while the vehicle is running. You should read no less than 12.5 volts at idle with no accessories running and no less than that with accessories all on. Normal volts should be around 13.5. Aside from slight fluctuations, the voltage reading should not steadily drop, regardless of how long it is running. I doubt if you have a system drain if it's shutting down while driving...the alternator would compensate for that. Some charging systems incorporate the voltage regulator into the computer. If the alternator checked good by itself but the tests I recommended show otherwise, likely your problem is with the computer.
If the engine does not need to be jump started after it shuts off, you may be looking entirely in the wrong place...but you didn't mention that part!!

Yes, this sounds like a flat battery. You could try to get a jump start off someone else, so that you know it is definately not the engine. Otherwise, purchase a new battery and you should be fine.

Take your battery to the parts store and have them test it. If its an original replace it anyways batteries only have a 5 to 7 year life span. on another note when your window walked off they may have damaged a switch in the door. this may be causing your display issues.

Connect your old battery with another battery from another car (WHILE KEEPING ALL CABLES CONNECTED ON BOTH CARS) just user a bridge cable otherwise you'll need. a code to reactivate your BMW again. Try now to start your BMW engine. Now go to the nearest battery dealer to change the battery WHILE KEEPING YOUR ENGINE ON, otherwise you'll need a code to activate your BMW again :)

Good Luck!