Strange voltage on accessory ignition/stereo switch
Okay guys, here is one of the strangest ones I have ever encountered:
My battery went dead last weekend. No biggie right. Unfortunately not. I also found the stereo dead as it had blown the fuse that protects the accessory/switched side. Repalced the fuse and charged the battery. What seems to be the cuase of the dead battery is the stereo staying powered on, but only sort-of. My DVM indicates nice 12.7V solid on the accessory/switched lead at the stereo coming off the ignition switch when only placed in the accessory position. Turn off the ignition switch and remove the key and the voltage remains present, but DECAYS very slowly. I can sit there and actually watch is slowly decay. It will start at the 12.7V, then drop to 12.69, 12.68 and so on. I have only been patient enough to watch it decay to about 10.9 volts before I was tired of watching it and switched on the ingition back to acccessory, only to see it jump back to the solid 12.7, then off and it will slowly decay again. I am certain it is not phantom voltage as it will supply enough current to power the stereo even with the ignition switched off, for some time. My current hypothesis is that this may have happened over the weekend, the radio staying powered on after removing the key and as the voltage continues to drop, the stereo continues to try to pull more current till it finally pulled too much for the little fuse. I find it hard to believe it could pull enough current doing this to drain the battery, but the truck has not been driven much lately and the battery may have been low anyway.
Anyone know of any component in the system on the accessory driven circuit that could have a capacitance effect of allow the voltage to trickle? My first suspicion is the ingition switch itself and I plan to investigate it first chance, but figured I would ask the group first. I did search, but had a difficult time coming up with a viable search string. Anyways, thanks for the help!
Pain is weakness leaving the body