electrical problem

[davidharvey14]

replaced alternator new battery n replaced wiring harnesses 3 times... still drains battery n resets dsm link i have no clue ### to look for ne ideas on ### this problem cld be i was thinking the starter?

 

[gofer]

This is the write-up pulled directly from the sites VFAQ Tech Articles to help find a short, partial short, or battery drain. Thank luv2rallye for his helpful info, there are a lot of members that have used this write-up and found their electrical problems efficiently. Tech Article: Finding a short, partial short, or battery drain

FOR THE CASE OF AN UNKNOWN BATTERY DRAIN, disconnect the negative battery cable terminal and connect the test light (or ammeter but read precautions above) between that cable terminal and the negative battery post.
[Note: Some aftermarket alarms have a surge current when battery is first connected so if using an ammeter instead of the light, connect a jumper between negative battery cable terminal and negative battery post first. Then connect ammeter in parallel to jumper and finally remove jumper. This will prevent any damaging surge from going through ammeter.]
Be sure the light is the only thing connected to the post - all other battery negative cables go on the other side of the light. The light is now the only thing connected to the battery in series with the rest of the car's electrical (don't try to start the engine with it in). The bulb will limit the current so you now don't have to worry about any short melting the wires. Don't use an LED as this will glow even when you only have 30mA of current flowing which is normal for ECU and radio memories. LED's also only conduct in one polarity so it's misleading if it's backwards.
[Note: If you are also going to be measuring voltages to ground you may want to use the positive post for the test light instead so you don't "raise or float the ground" for the measurements (there will be a voltage drop across the light if it's on, of course, to consider). Just be careful not to touch any metal when working with the positive battery terminal.].

THE LIGHT WILL GLOW BRIGHTLY if there is a full short. An open door will appear as a full short so it should either be closed, or it's door switches disconnected, or the fuses removed that operate items (eg. dome/foot lights) caused by an open door (if the test light goes out when removing these fuses, that is the circuit with the short).
THE LIGHT WILL GLOW DIMLY if either you have a partial short or normal devices are turned on (which you should turn off to then see how it glows).
THE LIGHT WILL NOT GLOW AT ALL if nothing draws any significant current (30-40 mA is an acceptable draw to power the ECU memory, radio memory, etc.).

THEN START DISCONNECTING, and removing fuses/relays, and switching off, one at a time (1) things that don't work, (2) suspected things, and (3) everything on that circuit. When you disconnect, or switch off, the item that is causing the short, the light will go out (so it's a great detection device). Keep in mind the short may be in the wiring or fuse box which is harder to find, but first check all the easier, more obvious devices and places. If the light always stays on no matter what item you disconnect, you probably have a short in the wiring. In that case switch off all devices one at a time to see if light goes out. If it does, then the short is between the switch and the device. If you still can't find the short, try removing all fuses and relays in both the engine and inside fuse boxes. If the light goes out then start replacing the relays and fuses one at a time until the light goes on (identifying the circuit with the short). If the light is always on, you will need to get a circuit diagrams manual to start tracing and disconnecting wires and unplugging harnesses until the light goes out or, without the light connected, start measuring voltages and circuit continuities.

 

[davidharvey14]

thank you