I just put on a new AC Delco altenator three months ago. I also have a optima red top battery. My car won't start without a jump, even if I run the car a little while to charge the battery. When I am driving my voltage gauge shows 14.0 volts. Is the altenator not charging the battery, or do you think that I might have a short. Also last week I took the battery to be tested. It was fine and they charged it back up. A few days later the car had drained the battery again. Any suggestions on how to trouble shoot the probem. I think that it might be the dc regulator. but I am not sure how to test it.


[Modified by Marcum_Marley, 5:23 PM 10/31/2002]

 

It s a rare case but I have seen where the vats reader in the column is bad and can drain the battery.

 

Well, I have never disabled the vats on my car, and I have had problems with it. It might be something to look at.

 

Can you check the altenator with a multimeter?

 

Get a mutlimeter and see if you have a sizable curent draw at your battery. You will always have 50mA or less of draw for memory. (To measure the amps, disconnect the battery and run the mutlimeter in series with the battery) After that, start pulling the fuse out of the fuse box until it goes away. If that doesn't do it post back, I can tell you what to look for search for a draw next.


[Modified by dgoodhue, 1:06 PM 10/31/2002]

 

Ok, I need to check the battery while it is disconnected from car. After that do I reconnect the battery and start pulling fuses until there is no size-able current drawn from the battery?
Thanks Marcum,



[Modified by Marcum_Marley, 6:12 PM 10/31/2002]

 

You might want to try unpluging the under hood lights and see if it is still draining, some have had problems with them staying on or being intermittent.
If not then you will have to hook a meter up.

 

First, at night check to see if the underhood lights are out and that the vanity mirror lights are also out. Remove the neg cable and put an ammeter (VOM testmeter) from the battery to the neg cable and start the ammeter out on its highest scale because the courtesy lights draw several amps. When the courtesy lights time out, switch the ammeter to lower full scale so you can read the current. The normal leakage current should be less than 50 ma. My 87 draws 28 ma. If you have significant leakage current , start removing the fuses one at a time and watch for a sudden drop in current. That circuit will have the leakage and further tracing will be necessary. If no fuse pull reduces the high leakage, then remove the wire on the alternator output. If leakage drops, then you have a defective diode in the alternator. There are 8 circuits with fusible links under the jumper terminal next to the battery and these can be removed one at a time to further find the circuit with leakage. Don't connect the battery if you measure high leakage current or the battery will be discharged. If you measure normal leakage current , then you can suspect the battery not being able to hold a charge. You can test the battery by charging it up and let it sit disconnected for several days and then reconnect it and measure the battery voltage with the headlights on. The voltage must not be below 12.0 volts or the battery is at the end of its life.

 

Just a small reminder. You can't leave the keys in the ignition when the car is parked for extended periods of time. It will drain the battery.

 

i found the mercury switches under the hould dide not turn off the ewngine compatment lightsremove tehe glass and pull the mercury switch, all ok
hal 88 vert red :cool:

 

Hi.
I have an 85 4+3 Z-51.
I had the problem and it was the courtesy lights comming on after they had switched themselves off with the timer. To check if it is the courtesy lights take the fuse out and see if it will be better. For me it helped and I have to take off the white enabling cable from the timer under the dash on the passenger side.
It could also be that it is the door switches that are bad. Especially the hatch switch. Check the door switches for proper operatiuon.

 

If your battery is discharging rapidly, like overnight, one of my first places to look would be the alternator. Even if it will charge to battery while the engine is running you could have a short in one of the diodes which will drain the battery while parked. :chevy :chevy

 

This happened to me on my last trip to Colorado. It was my stupid mistake. I had inadvertently turned the interior light on at the light switch and since I only saw the car in daylight I never saw the interior light on and I kept draining the battery. When my wife pointed it out to me I really felt stupid.

PC

 

i had an 85 that was draining battery because of the digital dash internal problem,pull the cluster fuse after you park it,wait a day and put it back in and see if she starts like it should. also let us know what you found out when you do find the problem. :cuss

 

Marcum,

I own an '89 and i am experiencing similar problem ... let me know what worked for you ... thanks to all that posted for the advice

 

Look at the rear view mirror and turn off the map light.