Cadillac Repair: electical problem, fleetwood brougham, internal corrosion

Question
QUESTION: i put a new alternator and a new battery in a 1988 Fleetwood brougham and the battery still will not hold a charge. could you tell me what else it could be.
thanks, Bob

ANSWER: How many amps is the electrical system drawing from the battery as if the car was going to sit overnight ?. maximum amperage draw is approx 1/2 amp.

Did you slow charge the battery for about 8 hours before you installed it ?.

I have in many cases found out that a new battery is NOT fully charged when you receive it and will be dead within a few days if not charged after or before installation as said previously.

Is the charging system working ?. just because you have a new alternator does NOT guarantee that it is working.

NO, You cannot use a test light to test the draw on the battery as the test light will illuminate due to the 1/2 amp draw that the computers are using all the time.

---------- FOLLOW-UP ----------

QUESTION: why else wouldn't the charging system be working. i did charge the battery. i have had multiple batteries and alternators in the car. i have brought it to mechanics, and it would run fine for a couple of months. then it would start the same thing all over again
Bob

ANSWER: It is possible that something in the car is operating intermittently causing the battery to go dead.

QUESTION:

Does the illuminated entry work all the time or only once in awhile ?.

It is possible that you have a problem with the air pump for the air shocks where the air pump runs intermittently during the night causing the battery to go dead.

What on the car does NOT work or only works sometimes ?.

It is possible that you have an intermittent faulty battery cable due to internal corrosion in the cables that prevents the charging system from charging the battery correctly at certain times.

You could have an intermittent fault in the POWER MODULE which is causing the AC/Heater blower motor to run at night thus causing the battery to go flat.

There are numerous possibilities.

Try and think what only works sometimes or any other odd things that occur.

---------- FOLLOW-UP ----------

QUESTION:
what is a illuminated entry? i will try the cables.thanks Bob

Answer
Illuminated entry is when the doors are locked and you try and open the door the interior lights inside the car illuminate.

It is also used when you get out of the car at night and close the door but the interior lights stay on for 30 seconds or so and then they go out.