Ham7

I don't want to post here in motorcycle stuff. but i need replies quick b/c i am leaving with the bikes tomorrow.Im sure someone has either had this problem or is a "real Mechanic" need opinions!!!

In my 99 gmc jimmy it has 12 volts of draw. I did a few test to see if it dropped, took each fuse out, took power off alternator,removed keyless/remote start,removed radio. Tryin to find what is causing the draw.
It wont start after sitting for like two minutes anymore, gradually has gotten worse as it has been getting colder. Took the + off the battery, placed the - lead from DMM (meter) on positive, then took + lead from DMM and put on positive power wire that goes to car. Read -12.10, i played around on the starter trying to see if i took off its ground if it would go away, it di not. so i took starter out, still nothing. put back in and decided that i would run continuity test it was far from open, was bouncing all over. Then i tried to test and see if it was grounding out between battery and starter, it was the same reading on meter at + of starter as it was at battery wire by the battery. Any ideas of what could be next. The battery under no load is at 12.00...or close to above. As soon as i put the power to the battery it drops by literally like -.5 volts off the get. When i cranked early in the day it dropped to 5.6 and obviously didn't start the car..,..i hate not knowing what is going on, but it seem like there is something going on in the starter mech. Could the starter have short making it do this? or is an electrical Gremlin that i need to tack down??? thanks, mike

Went and checked battery, checked out fine...think its my starter drawing current in the cylinod,,maybe running even though it doesn't need to be.

thanks for those who will help out in time of need!!!!!!

bink98xcab

hey man check if its the alternator, if it is bad it can casue a draw from the insides bein shorted.

crashtest 750

the voltage regulator in the alt is stuck. if you hit the alt with a hammer it might pop and work fine but since you are leaving with the bikes I would just replace it.

Ham7

so i charged the battery all night on 2 amp trickle, read 13.0 when i took it off. took it to advance auto, tested, said it was bad. Then proceeded to take it home and hook it up and see if it starts, read 12.5 unhooked, started, then took it to check the whole system on car, test showed good battery, good alt, and good starter??????????

turned car off, checked voltage with meter, showed 12.79 then .78.. .77, .76..so on,,down to like 12.6, then restarted..slower this time, turned off, battery still dropped back down again. started slower again.Right now it is sitting at 12.56 volts. gonna wait a while and go check again to see if it drops.

You all still think it is just bad. Or sound like something else.

Ham7

just checked it again while it hooked up, it read 12.52..so it has dropped by .04 in like 20 minutes...this is so weird

bink98xcab

voltage sounds normal to me, if that sisnt fix it , it must be the alternator

Wheelie Ripper

First things first, you do not test draw with voltage. You need to hook your multi-meter up in inline with the + or - terminal an cable and have it set on the 10 amp setting. I would make in inline jumper wire with a 7.5 amp fuse so if you have a huge draw it won't pop the fuse in the meter. Up to a 30 milliamp draw is considered acceptable .030 amps as a maximum, most new vehicles are around 12 milliamps. It is normal for a battery to drop voltage after a charge. usually 12.4 volts or higher is ok. I have seen batteries that have 12.6 or higher volts that are bad because of a bad cell inside. I would check the draw again and if you are within specs it may be the battery. Make sure your doors are closed and keys are out of the ignition when doing the draw test. If you have anymore questions feel free to PM, I was a GM certified tech for the past 6 years.