Car has electrical short somewhere. I have lots of experience tracing electrical problems, but not in cars per se (I am an engineer who worked with factory control systems, and data collection systems). Car sat for appx. 1 month and then when I tried to move it battery was 100% dead. I put volt meter across terminals and got ~0.5V. I then disconnected battery and checked again and got ~4.5V. This told then and there that there is probably a short, as something was bringing both battery cables to same potential. To confirm I checked resistance between cables and got ~2.5 ohms (and if I put the fluke on "ring mode", it rings/shows continuity). To be sure I wan't missing anything, I did same checks on our good car and got readings that I expected (~12.9V accross battery, very high resistance between cables). So I am wondering the following: 1. Why didn't a fuse blow, 2. Is it same to reconnect a battery to see if I can start it (to drive it to a servicer for further diagnosis and repair). My thoughts are 1. Perhaps the short is ahead of all fuses, so none blew (but there may be other more logical explanations), and 2. On one hand the battery was connected until a few days ago. But on the other hand, a dead short means a whole lot of current will be drawn once the battery is there and have strong concerns about starting a fire (or worse.I have seen what batteries can do when the terminals are dead shorted).
Wednesday, January 23rd, 2013 AT 9:38 PM