What causes the battery of a Ford Ranger XLT to keep loosing charge when as soon as you turn the key the power is gone and it will start when you have cables going to the battery?

Answer 1

I had the exact same problem with my ranger - its a 1990 Ford Ranger XLT 2.9L EFI V6. I replaced the battery, got a bad one the first time. Put in a new one, let the truck sit for 4 days and went to crank it up, completely dead. Jumped the battery, got much more power than before. Removed the cables from the Ranger, ran for a minute and then cut off. Attempted to start, wouldn't turn over. Jumped it again, struggled to start but finally cranked over. Removed the cables again, same thing. After 3 attempts, wouldn't even jump start. Then noticing the starter was still working but the alternator was not turning over completely anymore. Took it out, had it tested at 2 Auto Zone locations, both couldn't get a positive read on the tester. Alternator was bad. Decided to throw in some new spark plugs, wires, distributor cap, rotor, and ignition coil prior to putting alternator back in. Would love to say it runs fine but I haven't actually gotten the alternator in, nor have I managed to replace the spark plug wires or the final spark plug yet... Can't currently reach last one and connected the distributor cap wrong so now not sure how to wire the plugs back... Have the alternator tested, if the answer from before is not your solution. (My ranger is still equipped with factory parts, minus the few upgrades ive completed so far - this thing went from a beater to a junker in no time flat.... I payed $650 for it but I've already put an additional $800 into it in a matter of 2 months :) I love it, lots of discoveries every day) Weak battery? Light on glove box trunk etc. Bad voltage regulator Connect a test light in series with battery terminal then remove one fuse at a time to determine which circuit is draining battery. with current flowing the test light will illuminate when you disconnect fuse on circuit that is draining battery test light will go out allowing you to isolate problem