My 74 has had electrical problems for a few years. It is my wife's and she doesn't drive it often. Occasionally it won't crank, the radio and wipers have not worked for a year. In the past I have replaced the starter, it tested bad, the dash harness and the engine harness. I have spent hours with a voltmeter tracking where the power is and isn't. Finally I narrowed it down to the ignition switch. I dropped the steering column and swapped the old for new. Before installing the switch I ran the switch through all positions using a screw driver in the slot. Everything worked for the first time in years. Happy, I installed the switch per the directions that came in the box and put the column back in place. Nothing worked. No cranking, no wipers, no radio. Frustrated I dropped the column and pulled out the switch. Everything worked using a screwdriver in the slot. I reassembled per instructions and tested it with the steering wheel resting on the seat. It worked fine. I blocked the wheel up high enough to connect the rag joint and tried again. Still fine. I got bolts for the column that are one inch longer so the column hung low. Still fine. I completed the installation. Nothing worked. I dropped the column back to the seat. Nothing worked. I removed the switch and cycled it with a screw driver. Everything worked. Put the column back up. Nothing works. Dropped it back to the seat. Nothing works. And that's how it sits right now.

 

Sounds like you've got a mechanical pinch or break happening somewhere when in position. Have you followed each wire down the column and to the "harmonica" connector looking for broken insulation? When it's all up an in position, do you have main power at the harmonica?

 

The harness is new and everything looks good. There is power coming in. There is some mechanical looseness up at the key switch. I'm considering getting a bolt about 1/2" longer and putting some spacer washers in-between the column and dash to see what that does. The long bolts I have are only threaded at the very end.

 

Now that I think about it I have only checked for power at the ignition switch connector with it unhooked. More checking is needed. Thanks.

 

The switch should have oblong holes so you can slide it along the steering coolmn. It sounds like you need to slide it further away so the rod from the key does a better job of engaging the switch locations

 

That's what I was thinking but the switch is off the column now and does not work when cycled with a small screwdriver. It had been working like this. I'm now looking for something that is close to the column that gets bumped when I remove/install the column. I'll focus on the large plug in the firewall.

 

Have you looked at the plugs that go into the ignition switch? You might have a bad connection in one of them with the power wire. The power comes from the horn relay and goes through the body connector from the headlamp harness into the fuse panel and from there to the ignition switch.

 

could be broken wires inside the wire harness or in the insulation of the individual wires

 

After much checking with the volt/ohm meter I found the problem in the wire running from the power junction in the engine compartment to the plug in the firewall. This wire is part of the forward light harness which didn't get replaced because I didn't know that there was a main power line in that harness. I ordered a new one and installed it today and now everything works.

 

Good job!!!!