How to find a short to ground
Disconnect the positive battery cable and put a test light between it and the positive post. IF you have a drain, the light will light.
Now start pulling fuses until the light goes out. TAKE A PICTURE OF YOUR FUSE BOX FIRST! you will want to put the fuses back in their correct positions (different colors are different amperages)
(NOTE: in a '66 you'll have the glass see through type of fuses that are not color coded. However you won't need to pull them all the way out, just pull one side out and tip it away from the connector.)
Then start putting fuses back in. If the light comes on, keep that fuse out and continue installing the rest of the fuses.
AT this point you may have one or more fuses out of the box, you will need a wiring diagram to see what components are on those fuses. Then you can start disconencting the components to take them out of the circuit, and then other connectors in the circuit, until you can narrow down where the short is. Be aware that there are some circuits that will be hot all the time, and create a little draw, such as the clock radio, and keep alive memory for the PCM, perhaps others.
Note: Using this method justaguy found a stuck relay. He said, "So I used your advice and used the test light. I went though all of the fuses and the relays again. I climbed up and took the wires off of the glow plug relay and then the air heater relay, thats when the light dimmed. I replaced the relay... so far so good!"
Tech Make your own short tester/locator
Disconnect the positive battery cable and put a test light between it and the positive post. IF you have a drain, the light will light.
Now start pulling fuses until the light goes out. TAKE A PICTURE OF YOUR FUSE BOX FIRST! you will want to put the fuses back in their correct positions (different colors are different amperages)
(NOTE: in a '66 you'll have the glass see through type of fuses that are not color coded. However you won't need to pull them all the way out, just pull one side out and tip it away from the connector.)
Then start putting fuses back in. If the light comes on, keep that fuse out and continue installing the rest of the fuses.
AT this point you may have one or more fuses out of the box, you will need a wiring diagram to see what components are on those fuses. Then you can start disconencting the components to take them out of the circuit, and then other connectors in the circuit, until you can narrow down where the short is. Be aware that there are some circuits that will be hot all the time, and create a little draw, such as the clock radio, and keep alive memory for the PCM, perhaps others.
Note: Using this method justaguy found a stuck relay. He said, "So I used your advice and used the test light. I went though all of the fuses and the relays again. I climbed up and took the wires off of the glow plug relay and then the air heater relay, thats when the light dimmed. I replaced the relay... so far so good!"
Make your own short tester/locatorBogHog said:
Tech Make your own short tester/locator
