instant power drain problem

[hollerg]

I have a ford taurus 93, 3.8 L engine. Car has been sitting idle a couple of months but started fine and passed inspection. Starting it for the 4th time that day, turning the key and nothing, all dash lights go out, no crank, no click, no prior warning of battery or starter trouble.

Tried charging and internal lights are very dim. Removed the battery and had it charged and tested. Was told it was okay. Reinstalled, clean terminals and get grudging turnover but never gets enough speed to crank.

Tonight I upgraded my jumper cables from light to heavy weight. Lights bright, dash looks normal. Turned the key and .... nothing, dark dash. Put jumper cables on it and idled a while, nothing, no lights of any kind. Like no power at all.

I realize I need a voltage tester, but wondered what is the most likely cause. The starter? battery?

[shorod]

You need to make sure the battery cables are clean and tight, both at the battery and at the other end of the cable. Also, are these OEM style battery cables or by chance has someone installed the temporary bolt on cable ends? If so, those are only meant as temporary and do not protect the copper wire from corrosion.

If the cables are good, clean and tight, then you could easily have a battery that cannot support a load. The quick load tests the stores perform are not always accurate.

I'm not clear what is happening when you used the jumper cables. It sounds like you connected them, the lights got bright, but when you tried to start the car, the dash lights went out. But then you say you put jumper cables on it and it idled. Were the jumper cables on when you had the bright, normal lights? When did you disconnect them?

-Rod

[hollerg]

The car has OEM battery cables - top end of cable is tight - can't get an angle to see the bottom end of the cable, because of where it is parked.

The lights were bright without cables being connected. I just tried to jump it again. Turning the key to the start position causes everything to go black and stay black when the key is released.

Interestingly there was no spark when disconnecting the jumper cable when this condition exists. I was about to give up but when I opened the car door full lights were on inside the car. I tried the key again and it went completely dark again. slaming the door again did not help the complete lack of power. I tried wiggling the negative battery cable and it brings the power completely back on, but each time I put the ignition switch to start it goes completely dark and stays that way until I get out and wiggle the wire. As best as I can tell without a push to a new location or jacking up the car, the cable is connected tightly.

Even after a few cycles of "going dark", wiggling the wire brings back interior lights, warning lights and strong headlights.

So do I work on the starter or the ignition switch, if the cable is intact? Also where is the fusible disconnect, in the negative cable? Is replacing an ignition switch hard?

[shorod]

I think you work in the area of the negative battery cable. You could also have a broken post on the battery, inside where you can't see it. I've seen it before.

When you try to start the car, there is a large current draw on the system. That current draw may be causing the connection to go open until you wiggle the cable/connection again.

-Rod

[vgames33]

Unhook the negative battery cable from where it bolts to the body, engine, etc. Clean the cable's terminal and where it bolts down. If this doesn't help, I would suspect an internally broken cable or battery post.