I have a 1998 Toyota MR2 (90,000 miles) with an appetite for batteries. This spring, the battery was dead, so I put a new one in. Two months later, I try to start it and the battery is dead again. In previous years, the car would go the whole winter (4 months) and start up just fine in the spring. So, I’m thinking the car has a short. Where to start?
I meant 1988, not 1998.
Plan on spending a lot of time tracing a parasitic drain. These are not easy to find sometimes, but always seem to take a while to locate.
To see if it is a high amp load, like a light the refuses to turn off, I like to use a single filament light bulb like a back-up light bulb. With a charged battery, hook up the positive, but leave the negative cable loose. Put the barrel of the light bulb on the negative battery clamp and touch the center to the negative post. If the light filament glows, it is a high-amp load. Remove fuses until the light doesn’t glow anymore. This is the circuit with the load. Use the fuse box diagram to locate what on that circuit is draining the battery. I usually start with the fuses for stuff like courtesy lights and cigarette lighter.
If you cannot find the parasitic drain, disconnecting the battery will prevent it from draining. There are some quick-disconnects available so you can do this without tools.