Lost electrical power; battery fine; what's going on here?!?


nelli82669
04-09-2014, 09:29 PM
I was troubleshooting a P0307 code (cylinder 7 misfire) on my 97 Grand Marquis. Suspected the plug wire may be bad so used an ignition spark tester to check it. Unplugged wire from the plug, connected it to the tester, grounded the tester to the battery terminal and adjusted tester to 30K volts. Started engine and tester showed strong, consistent spark. Turned off engine after ~30 seconds, re-adjusted tester to 40K volts, then went to start engine. Engine turned over maybe once, then stopped. Voltage gauge in instrument panel showed no voltage and headlights/blower/windows/etc. had no power. The only circuits which had power were radio and interior dome light.
The battery has a 12.5V charge. I checked the high current fuses in the box near the battery and all were good. The high current fuse panel has 12.5V supplied to all the fuse input leads. Checked fuses in the instrument panel fuse box(inside car) and all were good.
If I remove key from ignition switch, reinsert it and move it to the run position, the voltage gauge rises maybe a quarter inch (8-9 volts?) but when the key is moved to the start position, the gauge drops all the way to the bottom and stays there until the key is removed and reinserted.
Obviously, a fuse or fusible link somewhere blew. Any idea where it might be?

nelli82669
04-13-2014, 09:00 AM
Never did get any replies to this posting, but managed to figure out what was going on anyway. Final outcome posted here: http://www.automotiveforums.com/vbulletin/showthread.php?t=901265&highlight=ignition+switch+wiring

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