Electric auto short

flattop1

flattop1

Dawg 89
A 4 amp drain that Iseem unable too pinpoint . Pulled all the high current fuses individually , all the interior fuses . Disconected the alternator . Nothing
Unhook the distribution box it drops too 2.3 .
Started with milli amp over loaded , switch to test light then 10 amp dvm .
Never had a starter draw current at rest .
Any suggestions . 96 town car new too me last week , and i saw the old guy charging it on a regular basis before i purchased .
Thanks tony
 
I need to refine my testing procedures .
Today after fiddling with it , look over and the glove box door is open .
Shut that , still high current draw , yes the light goes out .
 
There will be a wake up draw for the computer when first hooking up battery, then current should drop to milli-amps.

Did you get in glove box to make sure light went out? ;)

Dome light on because car door is open? trunk light? under hood light.
Door light switch in trucks after that era have the switch built into the door latch.
 
Last edited:
10-4. I need to start over from the beginning . Had the door latch shut, hood light unplugged , the light goes out . I will pull the bulb.
 
Since you probably don't have the proper switch to do this. Disconnect the negative battery cable and connect a jumper wire from the battery post to the negative battery cable. Wait 15 minutes and connect you ammeter from the negative battery cable to the negative battery post.
Carefully disconnect the jumper wire without disturbing the ammeter.
If it still reads high do the whole process again and wait 1/2 hour and do it again.
It can take a long time for all the electronic components to go to sleep.
If you still have excessive current drain you've got a problem
Does it have air ride control? if so does it work properly?
 
No real solution . Pulled the radio , seems to do the trick . Have not let it sit more then two days . So its still a maybe .
The DVM timed out when i let it sit for everything too go to sleep .
 
I watched an old mechanic chasing a high amp drain on an old Buick Electra 225 back in the 1970's. Now this is South Alabama need I say more ?
After 3 tries with slow blow 30 amp fuses he put a piece of brass tubing in the fuse holder, got under the dash and had me watch while I installed the battery wire. Says, "keep a sharp eye for smoke, this won't take long" LOL
Well this was years of experience at work. Smoked an owner installed wire feeding a "Reverb" under the dash. The wire was pinched at the fire wall and burnt all the insulation off back to the battery. LOL. He said, "takes less time to rewire these things than it does looking for the short".
Another lessen in my youth.
Best, WP
 
Thats funny .
That thought crossed my mind . I believe i will wait till it strands me some where .
That and stupid computers /body control modules .
Plus i got it down too a lot less draw volatge goes from 12.8 down to 12.2 in 2 days .
 
Last edited:
Just a thought and from previous experience. Have you unhooked the battery to see how much it drops on its own in 2 days? A bad cell will give you the results of a draw.
 
Tested another one , with a similar issue the dvm shuts off before i get back to it .
20.5 milliamps , must be good cause it will start after sitting a month .
 
I use a fuse buddy inline with the neg. post on the battery. Install alligator clips on both wires of the fuse buddy. Run a screw into the center of the neg. post and attach one alligator clip to the screw and wrap it with tape. Put one to the neg clamp then pull the neg. clamp off. Should not draw more than 500 milliamps. That way you never disturb the modules to wake them up. Another thing I do is take a screwdriver and latch the doors if I have to have them open to get to the fuses. I pull 1 fuse at a time till the draw goes away to narrow it down.
 
10-4 i used jumper wires , on my test vehicle , sat 2 days with hood unlatched . Watching the meter. Is like watching paint dry . I move on too something else . Upon return its timed out .
 
You need a wiring diagram. Buy a manual which has a wiring diagram in it for your car at Autozone.

It should be simple to find. All you need to do is probe your fuses with a low voltage test light. When you find power check the other side of the fuse to see if the fuse is good, then remove the fuse and again check both sides. If you only have power at one side of the fuse holder go to the wiring diagram and see if it should be there with the key off. If it should then go on to the next fuse and do the same. No reason to look at any circuit for physical problem until you know which is involved with feedback or is on when it shouldn't be on. It's really that simple. Same way if your trying to find an intermittent open. As long as you have power at the fuse on both sides when you should and something doesn't work it has to be open on out away from the fuse on the wiring diagram. All you have to do then is find other points to check on the open circuit looking for the test light to go on or not. The only hard part is finding and getting to the places to check per the wiring diagram. You can probe most any connector by forcing a straight pin down into the connector or you can poke somewhere on the wire your checking for voltage. Electrical problems are cut and dry if you have a wiring diagram, even flakey grounds. The next thing is if it looks flakey you have to touch it with your hands and unflakey it ground or connection. The hardest thing is to find something look at it and not be able to believe or tell yourself it's really a problem. Finding electrical problems are easy. Making yourself believe you found it can be and is often tough! You've probably had your hand on the problem and didn't know it. ... :)

If you can't learn to relate tracing a wire on a wiring diagram to tracing the same wire on the car, your spinning your wheels waiting for dumb founded luck to help you out. Some times it does and sometimes it doesn't.

A simple thing like looking at the diagram under the inside of the cover of a fuse box upside down can get you totally confused because everything you look at fuse wise in the fuse box is backwards.
 
I like WPauls idea . Let the smoke out of the wire . Problem found .
The manuals i have do not indicate which are hot key off .
 
paulkish said:
A simple thing like looking at the diagram under the inside of the cover of a fuse box upside down can get you totally confused because everything you look at fuse wise in the fuse box is backwards.
Click to expand...

I have never been beat finding an electrical problem in a car with a test light and a meter.

I've beat myself though many times not being able to believe what I measured.
I tend to have to find the same problem 6 different ways before I believe it and then only after it's fixed do I accept what fixed was fixed was really the problem.

I think it's because in my work if I was wrong on a diagnosis it could shut down things like maybe the east coast. ... :)
That was a slight exaggeration but only slight and more like only a major factory or business in the area. ... :)
Anything wider spread usually but not always had backups in place to prevent stupid stuff from crippling them.
Butt not always.
 
flattop1 said:
I like WPauls idea . Let the smoke out of the wire . Problem found .
The manuals i have do not indicate which are hot key off .
Click to expand...
Thats how you pinpoint a short to ground. And sometimes it is necessary. There is a tool that will pinpoint those too.
 
Put a test light between the neg post and battery clamp. When it has a draw it will light up. After you make sure the modules are asleep, the test light wont light up unless there is a draw. Pull fuses till the light goes out and let me know which fuse it is.
 
You must log in or register to reply here.
Back
Top