dasjestyr@gmail.com

So i got home from deployment to find that my car was impounded. got it out of the impound lot and the battery was dead. got a jump and drove it to my girl's place. was dead again as soon as i shut it down but still had enough juice in it to power the door lights but not start. got a jump, drove it an hour back to my place just fine, shut it down, dead again, with just enough juice to power the door lights but not start. Replaced the battery, jumped it, disco'd the jumper cables, ran it for a half hour, noticed that now the speedo and tach dont work and the speedo is pointed straight down, shut it down, COMPLETELY dead, no door lights or even a clock.

im inclined to believe the alternator is fine since it'll run for an extended period of time after a jump, but why isnt the battery charging, and why is my speedo/tach all of a sudden not working after i changed the battery?

any ideas?

P_Adams

Clamp a multimeter between the Battery terminals and determine what the Battery is seeing from the Alternator. With the engine running and most of the accessories on, you should see no less that 13.89 Volts. If you do not;
See if you can gain access to the back of the alternator and with the engine running (and avoiding the wire terminals) place a screwdriver's blade near the vicinity of the rear rotor bearing. If the Alternator is charging, you will detect a magnetic field. you can also probe the heavy wire terminal with a multimeter, you should see no less than 13.8 volts there as well.
You might want to check the large 50 amp fuses in the engine compartment fuse box, particularly the one marked "Battery"
Let us know what you find

P

steven_b_03

also, what I did when my car was doing this, is loosen the negative cable on the battery (with it still touching for a connection), get the car started, and while it's running pull the cable off the battery...if it dies, alternator, if it stays running, then I don't know, possibly bad battery.

edit: Almost forgot, mine ran fine too for a little bit, but my cd deck has a built-in battery meter (not accurate but close) and once it got below 9v everything switched off...turns out a diode was going out, and when it was checked at various shops it ran fine because of no load on it...

dasjestyr@gmail.com

yeah turns out that it was a bad battery. i did all the electrical tests and like is said the alternator actually was fine lol. so i told them to swap the batteries and bam, perfect. weird.

P_Adams

Glad it worked out for you.
Sometimes it's the simplest of things, huh?

P