'54 Mercury, hot wire to buss bar & curcut breaker

[indyhac]

I just installed a replacement ignition switch and a headlight switch. My starter was trying to engage after I turned the key off and my dash lights weren't working; figured I might as well replace the headlight switch while I was working on the key switch. Anyway, when I hooked the battery cables back up, I discovered that something was putting a drain on the battery. Replaced the starter solenoid and then the voltage regulator which cured this. Trouble is, now there is no power to the key switch nor to the light switch. I've tested what I believe to be the hot wires coming from the solenoid to the buss bar behind the dash, which is to the right of the steering column. My meter displays no voltage on either wire as though they are disconnected from the solenoid but they are connected, the light wire to the battery side and the key switch wire to the starter post side. According to my shop manual ignition wiring diagram (I'm not the best at reading wiring diagrams) the big fat yellow wire that goes through the loop on the back of the ammeter, then to the buss bar is the hot wire to the key switch. If anyone has any suggestions as to what could be causing the loss of voltage from the ignition wire and the light switch wire at the buss bar, I would certainly appreciate some help concerning this dilemma. Note: Fords have an idiot light instead of an ammeter so I don't know exactly what a Ford wiring diagram shows. Also, the battery is fully charged and the convertible top motor and the electric window and seat motors all work. They hook to a different buss bar behind the driver side kick panel.
Thanks, Scott

[miker98038]

I don't have a Merc, so I'm shooting in the dark.

My bird originally had a feed from the battery side of the solenoid to one of two circuit breakers under the dash. I think one had a stamped copper plate (buss bar?) to the other on the feed side. One breaker fed the ignition, and maybe the lights, the other the power seat.

Is it possible one of the breakers (the one to the ignition) has failed due to the other problems? Do you have power on the feed of one, but not the other, or on the output of one, and not the other?

If you've got power on one end of the wire, but not the other, either it's the wrong wire, or it broke or melted. Did the lights not work because of the switch, or some other problem?

[Daves55Sedan]

If I remember right, on a Ford of that era, the big yellow wire (Hot) runs from the battery side of the starter solenoid on the fender apron and the other end connects to the batt terminal of the light switch. Then another big yellow wire jumpers from that light switch terminal to the batt terminal of the ignition switch.
The Fords didn't have an ammeter. There is a little yellow/black wire that runs from the voltage regulator that operates the generator idiot light.

[rick55]

It sounds like you may not have the wire connected to the battery terminal of the starter solenoid. It should be bolted to the same terminal as the main battery cable. The yellow wire is a cable capable of carrying 40Amps and should not suffer any damage in normal service.
Dave's comments are correct for this era Ford but if Mercury use a buss bar, the wire should be live. If it is connected at both ends it must have been cut, shorted etc. run a new wire and see if that fixes the problem.
If your car was trying to start when in the accessory position you either had the switch wired incorrectly or the switch was faulty.

[indyhac]

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Yep, you're right. Somehow when I changed the solenoid, I had that big yellow wire laying over by the other side of the solenoid and connected it to the wrong post. Lights and starter work now but something is drawing 12 volts from the battery when I connect my multimeter between the negative battery cable and the negative battery post. I should add that my Mercury has been converted to 12 volt, negative ground. Now I have to solve that problem.
Scott