67 wiring issue

[Jeremy H.]

I am just finishing a frame off, new wiring and everything. I keep blowing the 20 amp fuse. The bottom one on the panel. What all does it control? It says Clk, ctsy, haz, ltr. I assume that is clock, lighter, courtsey lights and hazards. Anything else? My clock works even with the fuse out. I don't have courtesy lights, lighter and I am not sure about the hazards. Any ideas?

Thanks

Jeremy Hedges

[Ray G.]

Re: 67 wiring issue

Hello Jeremy;

Most common situation w/ lighter etc; fuse blowing is the lighter receiver.

Have seen many incorrectly assembled lighter bases.

Look for center receptor prongs to be wrong or not insulated.

Hope this helps.
Ray

[John H.]

Re: 67 wiring issue

I assume that is clock, lighter, courtsey lights and hazards. Anything else? My clock works even with the fuse out. I don't have courtesy lights, lighter and I am not sure about the hazards. Any ideas?

Thanks

Jeremy Hedges

Jeremy -

That fuse also feeds the glove box light. If the clock works without that fuse in place, someone has messed with the wiring.

[Jeremy H.]

Re: 67 wiring issue

It is brand new wiring that I installed. I have unplugged the lighter and still it blows, I will try and disconect the glove box next.

[Ray G.]

Re: 67 wiring issue

Hello Jeremy;

Follow the wiring diagram in the manual or;

A couple of optional ways to proceed;

Unplug everything and then start reconnecting each item. Include the gauges, directional switch, and ignition switch.

Also you can try connecting a variable load directional flasher across the the fuse contacts to save fuses. It will disconnect when the draw or short is happening and then obviously reconnect, etc. This method can be called "smoking it out".

Another wire that pops into the mind is the dark brown ground wire that plugs onto the ground spade at the top of the dash cluster. Make sure it's not plugged into something incorrectly.

Hope this helps.
Ray

[John H.]

Re: 67 wiring issue

Another wire that pops into the mind is the dark brown ground wire that plugs onto the ground spade at the top of the dash cluster. Make sure it's not plugged into something incorrectly.

Hope this helps.
Ray

Ray -

That dark brown wire connects to the radio capacitor mounted adjacent to the ignition switch, and is "hot" any time the key is in "on" or "accessory". The cluster ground wire that plugs to the spade above the tachometer is black.

If the brown wire is connected to the ground spade, it makes the entire cluster "hot", and it will then ground through the hood release or the oil pressure line, either of which will become red-hot when the key is turned.

[Ray G.]

Re: 67 wiring issue

Hello John and Jeremy;

Sounds like your correct. Have not looked recently.

Sorry Jeremy.

Hope all is well and tracing according to wiring diagrams never fails, just takes longer.

Ray

[Joe R.]

Re: 67 wiring issue

Jeremy,

I would recommend the following troubleshooting procedure:

1. Disconnect the battery. The battery will confuse the ohmmeter used below.
2. Remove the offending (offensive?) fuse.
3. Check to see how much lead resistance you have by shorting the + and - leads of the meter. It will make a big difference when you're looking at resistances this small.
4. Connect an ohmmeter between the load side of the fuse holder and ground. The load side of the fuse should ring (be nearly 0 Ohms) to the cigarette lighter, etc. Subtract the lead resistance mentally when taking all readings. So if the lead resistance is 0.1 Ohms and the meter is reading 0.7 Ohms, the resistance you are trying to measure is actually 0.6 Ohms.
5. Remove loads (cigarette lighter, lamps, etc.) from the circuit one at a time until the resistance seen is a reasonable value. It should be above 0.6 Ohms (12 V / 20 A). Otherwise the fuse will blow as soon as you try the magic smoke test again.

I don't like to troubleshoot using the fuse as an indication that the circuit is faulty. The wiring is stressed every time the fuse blows.

Joe

[Doug F.]

Re: 67 wiring issue

make sure you have double contact bulbs in the courtesy light housings, there are 3 of them,