Cannot start car with jumper cables

toyota
start
electrical-wiring
failure
corolla

#1

I have my daughters 2002 Toyota Corolla which I recently drove back from Washington DC. It is sitting in the driveway. I try to start it about every two weeks. The battery went dead. I tried to use jumper cables. On this first try the dashboard lights came on when the cables were hooked up. But there was only a small click from the starter and the dash lights went out. I assumed that the cables got disconnected. After many measurements with a volt and an ohm meter this is the situation. With the cables attached to a good battery at one end the clips read 12V at the Toyota end if they are not connected to the Toyota. If I connect them to the Toyota the voltage reads ZERO. I assumed that the Toyota battery has a short in it so I took the positive cable off the Toyota battery. When I hook the jumper cables to ground and the Toyota positive cable it also reads ZERO volts. With the Toyota cable off the battery I measured the resistance between ground and the cable. It is ZERO. I guess this mean there is a short somewhere? Where/how do I begin?


#2

First hook up the battery that is allegedly good to the Toyota cables and see if this results in a crank situation. Since you will then have the Toyota battery out, place it on a charger. Your first attempt appeared to be a common condition of a poor connection or the battery being so discharged that it sucked up most of the power provided by the jumping battery.

Not a GO - NO GO method you’re looking for, but I didn’t see a check of the Toyota battery with nothing hooked to it. This would not normally present a complex condition for me to move forward with in process/procedure. The dash light and click would point to a limited connection or one that was not left long enough to transfer enough current.

I would have hooked this up to a running vehicle and listen for the drag on the alternator. That would indicate the depth of discharge.

Someone will tell you to take it to AutoZone or some chain and have it load tested, but since it doesn’t have a decent charge on it, this would require them to charge it first. You can preempt that sequence by just hooking up the jumper (disconnect the Toy’s battery cables if you desire) cables and seeing if it will take it and load down your charging system. Chicken Little’s will be along in due time too to warn you of potential risk to your charging system.


#3

Getting up to the click was part way there. It may take 20 minutes or so depending on cables and battery condition to get enough charge to start the car.


#4

Unless you have some hefty cables and a heck of a battery in your own car, you just won’t get enough power across the jumper connection to crank the disabled vehicle if the battery isn’t helping you at all. So I would say the Toyota’s electrical system is probably fine, but the battery has likely completely cashed in its chips.

Like waterboy said, you need to let the battery charge for a good long time. If the battery is in such bad shape that it won’t take a charge, you’ll never persuade the car to start. And as an aside, if you were to somehow get it to start, running a modern vehicle with a battery cable disconnected (like you tried to do) can damage the electronics on the car—they depend on the battery to act as a kind of voltage regulator/surge supressor.

I’d just replace the battery. If it’s the original, it’s had a very long life. Even if it’s the second battery in the car’s history, it’s still fairly old.