Battery loosing charge?

My 94 Pontiac Transport has a tendency of of loosing charge in the battery. Battery is relatively new. The van runs fine once its started, so its not running off the battery, so I assume that charging system is working. The analog gauge shows to be a bit high, like at 16 volts. Sometimes it starts right up and sometimes it barely wants to turn over, even if I have been running it for a while. I thought I might have a drain coming from the sliding door circuitry because that has been screwed up for a while. I did all the usuall fixes like clearing the memory by way of fuse but it still work not work properly. So I changed out the sliding door module and the door works perfect now but battery still looses charge. I can put a heavy duty charger on it for 20 minutes and it act like brand new again, but then seems to go downhill after that. Is there any checks I can do on system to narrow down my problem. I have already swappped batterys to eliminate a battery problem.

Your problem lies with a short or open circuit somewhere in the van. Check to make sure the glove box light goes out when the van is off. Otherwise you will need to get a volt meter and pull each fuse individually to see if you can find the circuit that drains the battery. The computer will use a little voltage to maintain memory as will the radio but it should be minimal drain. Tracking down a problem like this one takes time and patience. Good Luck!!

You mean, check voltage drop at battery as fuses are pulled out?

I just went to start van and it fired right up. I let it warm up and stopped it.I restarted it about 6 times, no problem. 7th time it would not do anything. Idiot lights, chimes work. There ample power in battery to lower and lift both passenger and driver windows, but at turn of of the key nothing. Almost like no juice getting to starter or dead battery.

Looked around real quick to see if there was any current draw while van just sat there. Results were inconclusive. I looked at the Haynes manual for some pointers and it said to check starter and starter solenoid to see if problem is there or in ignition switch or park/neutral switch. It said to jump a wire from +battery to "S" terminal on starter. If it spins the neutral/park switch is ok and problem lays in the starter solenoid. Does that sound about right?Some of the wires going to the starter have been spliced before and look like some oxidation. If solenoid was defective, would that have a drain on battery?

It wouldn't cause a drain but the wires may not getting proper voltage to activate the solenoid when you turn the key. I would check all the wires to the solenoid to see if any of the wires are frayed or loose. If they are resplice and then retape or use shrink wrap insulation to keep the water out.

I ran a 10 gauge wire fro the +battery straight to the "S" terminal and got absolutely nothing. I tapped on solenoid and starter and still nothing. I moved flywheel by hand and tried it again and still nothing. I think the starter and solenoid are shot. Does anyone else agree?

If you did all that I have to agree that either the starter or solenoid are gone. Try a wrecking yard for a used one. Will cost a whole lot less than a new one.

Try a new starter

Just a follow up guys. I replaced the starter and everything is fine now. There is NO battery power loss anymore.

Yup.....good