They do. Did you ever stop to consider that there might be something wrong with your vehicle and not all 1988 BMW's? Guess not.
It may be that the battery has a dead cell, so you should fully charge the battery and have it tested at any auto parts store. If the battery is good then Start by checking all the accessory lights. Trunk, under hood, glove box, curtorsey, dome, all lights. If none of them are on then suspect a stuck relay. Power windows, seat, locks, etc.
Connect the bad battery to a good battery with jumper cables. Connect the positive terminals first, then the negative terminals. Now try to start the engine. When finished, disconnect the jumper cables in reverse order.
my battery is good but having problems with starting
If you are using it to turn on the car a good battery would help.
take the battery terminals off and clean them and the battery posts real good with a wire brush and reinstall and see what happens.
you can avoid draining the good battery
if the battery is good and charged sure
battery is good , c- pack's good will not start
I assume you had the battery properly tested under load. Its starts and runs when jump started so that tells me assuming the battery is in fact good that the battery cable connections to the battery are bad and need cleaning.
The battery seems to be a problem on this vehicle. A recharge could fix the issue but a new battery may be necessary.
try checking your fuses
It Would Be Best To Remove Your Battery, Clean All Connections While Charging Your Battery. Then Try To Start. You May Not Be Getting A Good Connection When Trying To Jump Start & Your Battery May Be Completly Discharged. When You Get `er Going Run By A Parts House And Test Your Battery. Good Luck