Electrical Issue

[Sierra John]

I was sitting in my car ('66 Town Hardtop) with the door open. After a few minutes, I noticed that all the interior lights were starting to flicker rapidly. There was also a sound like wires shorting out (sorta of an arcing sound). I closed the door so the lights would go out. Pretty soon, I starting hearing that shorting sound again, even though nothing was running (seemed to be behind the ignition switch). Has anyone experienced this? Any idea what's going on? As always, I appreciate the help.

[BillT]

I really can’t be of any specific help. But it’s unlikely a short that would cause the courtesy lights to dim is in the courtesy light circuit because it’s fused, i.e. the fuse would blow. It’s more likely a heavy short in an unfused circuit, Perhaps it’s a short in a circuit that’s circuit breaker protect which may explain the on/off blinking.

There is a relay (map light) that’s mounted, I think, near the fuse panel that is fed from the headlight switch. It’s possible, but unlikely, that the wiring to this relay could be shorting and the headlight switch internal circuit breaker could be turning on/off.

There are a few circuits behind the dash that are fed directly from the battery, e.g. the ammeter, ignition switch, cigar lighter, horns, etc.

Also, it’s a bit surprising, to me anyhow, that a 12 volt short will produce audible arcing, That is, it may be some other electrical device turning off/on that you are hearing.

Let us know if you find the cause, if the problem reoccurs with the courtesy lights on, or if you have any other noticeable electrical issues - to help identify the cause.

[David Langhorne]

I believe this is a common fault and I have had it a few times. It is probably the interior light relay up above the passenger side kick panel. This earths through its casing so check that first. Mine had a bad earth one time. Also if it happens when the headlight switch is on and the knob is turned fully anti-clockwise then it may be the contact on the switch which can be cleaned.

[Sierra John]

Thanks for the replies, guys. After a little more checking, I think I found the problem: dead battery.

[Sierra John]

UPDATE: The battery was dead, but that wasn't the problem. After I recharged it, the same problems (flickering door lights and electrical "noise") kept happening. I found that the power windows, seats, and horns had stopped working, so I checked the circuit breaker. It was red hot. I'm now checking the horn contacts, seat switch, etc. I think the electrical noise I was hearing may have been a seat solenoid or relay clicking.