C-2 Con-Fused?

[Chris R.]

Suddenly the courtesy lights and clock have stopped running in my 64 convertible. I immediately assumed the fuse was blown. When I checked it, the fuse looked O.K. but I decided to change it anyway.

The current fuse is a 30 amp. When I went to the owner's manual it showed a 5 amp (I think) should be in the Courtesy slot. A parts catalog I looked at showed a 20 amp fuse.

I used a 20 amp fuse I had in the shop last night but immediately blew it when I installed.

Any idea what fuse should go there? If it continues to blow, where would the likely source be? An article in the archives mentioned the door switches as likely culprits.

Thanks again for any and all help. Y'all are the greatest!

Chris Rose
Memphis, TN

[Bob R.]

Re: C-2 Con-Fused?

If a 20 amp fuse won't hold a glove box light and a clock you must have a short somewhere. If you check the AIM you could get the proper fuse size. I don't have that info available at my office however I would think the fuse would be 5 or 10 amp.

[Eugene B.]

Re: C-2 Con-Fused?

Chris,
Owner's manual for the '65 states that the Instrument, Radio, and Clock Lights is 3AG/AGC 4 amp.

Hope this helps.

Regards,
Gene

[Michael H.]

Re: C-2 Con-Fused?

Hey Chris -

Have you replaced the courtesy light bulbs recently? If you put the wrong type of bulb (2 contact vs 1 contact) you'll experince exactly what's happening.

[Chris R.]

Re: C-2 Con-Fused?

I checked the light bulbs, they are 2 contact and the socket is 2 contact. Now I'm beginning to think there is a true short in the system. I keep blowing 20 amp fuses when I install them. I've tried disconnecting the battery then installing the fuses. Same result, the fuse blows as soon as I reconnect the battery. I even tried closing the doors then installing the fuse to try to take the door switches out of the problem. Still immediately blows the fuse.

How can I troubleshoot this or should I take it to a shop? I have a simple test meter that tests volts AC & DC, Ohms, and Milliamps. Do I need another piece of test equipment?

Or is it just easier to replace the door switches and courtesy light sockets? Now I'm starting to get irritated!

Thanks,
Chris

[Michael H.]

Re: C-2 Con-Fused?

Hey Chris -

We've all been through this buddy, and I can emphatize with you. My advice is to print a copy of the dash wiring harness. Take a couple of colored felt fine-tip pens and trace/color code the appropriate circuits. Trying to read a wiring diagram is too confusing - way too much clutter! Once you have all the circuits highlighted, take a blank piece of paper and redraw JUST the circuits you're interested in. This will help you get a much clearer picture of how the circuit works and how to trace any problems.

From here it's a logical process of elimination - all you really need is a test light and maybe a multi-meter. Start at the far end of the circuit and test your way back to the origin - I promise you will find the problem(s). Try to avoid the conventional "buy parts and replace" approach. If you need help e-mail me and I'll send you my phone number.

Good luck,

Mike

[Dixon Green]

Re: C-2 Con-Fused?

Chris,

The circuit you describe powers the clock (not clock lights), courtesy lights, dome light, glove-box light and stop lights. The 64 shop manual indicates a 15 amp fuse, as does the fuse block itself. Without a circuit diagram, diagnosis will be difficult. But, here are some suggestions. To keep from using up fuses, use your ohm meter to measure the resistance between the right end of the fuse block and ground. If your ohm meter has audible continuity, you can listen for changes as you diagnose the problem. With the fuse removed, you should have about zero ohms in your current situation -- a short. By removing pieces of the circuit you may be able to isolate the portion of the circuit containing the short. Between each of the following steps check the resistance. Most of the wires in this circuit are orange-black. If you have an original clock, start by disconnecting the clock; the clock will be unwound and as a result it will have a very low resistance. Disconnect the orange/black wire to the brake-light switch. This disconnects the circuit through the turn signal switch, the body connector and wiring to the stop lights. Disconnect the body connector (nylon under the dash); this disconnects the dome light (and the stop lights already disconnected). Remove the courtesy lamps. Disconnect the wire to the glove box light. At this point nothing is connected to this circuit. If the short went away, look for shorts in the circuit branch just removed. If you still have a short, start looking for a some metal cutting into the dash harness. Moving the harness while listening to your meter is a big help at this point. Good luck.

Dixon

[Bruce Boatner]

Re: C-2 Con-Fused?

Chris,

I had the EXACT same problem with my 1964 coupe. Turns out that I fixed the problem by replacing the turn signal flasher (plugs into the fuse box on a '64). Easy enough to eliminate the flasher as possible culprit. Just pull the flasher, replace the fuse and see what happens. If the fuse does not blow you know either the flasher is the problem or you have a short in a wire feeding the turn signals. I found a replacment flasher for about $2 at the local auto parts store.

Let me know when you find out what the problem is.

Bruce