1989 town car battery drain help

[Kye Unruh]

Drains battery in about 12 hours. I unhooked the 5 wires at the starter solenoid and found the wire that was using power, it is a yellow wire that runs along the front of the car. I have unplugged the alternator wires, all fuses and relays, ignition switch, radio, seat power motors, main light switch and a few other items without it changing the draw. My clock does not work and I read somewhere that it could do things like that. Does anyone have personal experience with anything like this

 

[11MarkX]

Without a picture of your solenoid, I'm just guessing about the yellow wire. Diagram below is for late 80's mustang so it should be similar or the same. There's 2 yellow wires. One starts out green or black then becomes yellow under wire loom. That's for the regulator.

The other yellow wire is the primary 10 gauge wire which connects to fuse box and that line always has power, so it runs almost everything electrical on your car. Since you said you disconnected every fuse, relay in the fuse box and the ignition switch, did you try disconnecting the fuel pump relays under the hood? They're not in the fuse box. Regards,

 

[Kye Unruh]

Thanks for the help. Yes I did pull the fuel pump relay with no results. I just changed it because the old one had been stuck on which was also draining my battery but apparently there is another power draw yet. The power draw is through the yellow 10 gauge wire

 

[11MarkX]

Since you said the drain is only coming from the yellow line and that your sure you disconnected everything on that yellow line and its still draining, then it might be the connection on the fuse box is corroded/shorting out on something or the yellow line itself. The yellow line has fusible links installed. Its rare but if a faulty fusible link shorts out on steel or another wire by melting, it might not blow and still work, but will drain the battery.

If it was a minor drain (about 5 days to drain battery), maybe install an on/off switch on the yellow line, hide it somewhere in the interior and use it that way? But you said it drains within 12 hours. That's dangerous and needs to be fixed properly before a fire occurs. Regards,

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[Kye Unruh]

Found the problem. In all my infinite wisdom I forgot that the lights were all turning on in the interior,because my door was open,when I checked the draw therefore I did not catch the change in draw when I unhooked the alternator. Guess I’ll be buying a new alternator

 

[Kye Unruh]

Got it fixed with voltage regulator from junkyard

 

[oktowncar]

Got it fixed with voltage regulator from junkyard

Glad you got the issue resolved. Thanks for the update