More than likely I'm over thinking this, but I'm wondering if just the age of the wiring in a '70s or earlier vehicle is a safety issue in general? Is it a fire hazard simply because it's old? I'd appreciate some input.

 

No, there is no danger in using the existing wiring in an older vehicle. The only concern would be an old 6V car converted to 12V. Or in the case of a 70s 442 any aftermarket accessories added improperly to the wiring harness (ie. CB radio, electric choke, HEI ignition, etc.).

 

If the wiring is not melted, discolored, brittle, cracking, or frayed, it is not a safety issue.

 

As long as there aren't a bunch home done "upgrades" to the wiring. And even with those the most your looking at is damage to equipment. With everything running through the fuse panel, you're pretty well protected.

 

Everything does not run through the fuse panel. Start, headlight, and most charging wiring does not. On some later cars there are fusible links under the hood.

 

Excellent point on wiring safety, Eric.

On older cars, always add fusible links to the unprotected circuits.

 

X2... Agreed and can't say much more if the intention is to keep the vehicle original... If originality is not a concern adding fusible links and power shut offs (for long term non-use) can't hurt...

 

My 70 has good condition wiring except where some Gomer(s) worked on it.
A lot of auto mechanics don't know how to properly repair wiring- or don't care.
I would check for improper alterations, bad routing and of course condition.
Every electrical problem on my car has been due to bad maintenance.

 

THAT is definitely usually the case, other then the occasional corroded connections that can occur over time for any number of various reasons...

 

Agreed, corrosion is a biggie. I have cleaned grounds as I access them just to prevent issues.

 

While I agree that there is no danger posed by old wiring, there IS one issue to be aware of (besides half-fast work by a previous owner). Connector terminals do corrode over time, especially the unsealed Packard 56 series connectors. As this happens, resistance builds up, which can cause heat in a high-current circuit. At a minimum, check connectors for clean terminals and to verify no evidence of heating or melted connectors. Ironically, the 1980s cars are among the worst for this. The 307 cars have a four terminal connector near the distributor that connects the HVAC harness to the main engine harness. One of these wires is the high current feed to the blower motor. On at least two of my cars, I've had that terminal corrode and overheat, melting that connector.

 

To clean your connections I have found that CLR works really good, brings them back to new and will not harm the connector body or wire insulation . Put it in for 30 minutes and rinse it off. Dry and your back to new again. If you can pull the copper ends out of the connectors and give them a quick brush with a stainless steel brush they are nice and shinny.

 

Thanks guys - really appreciate the comments.

 

Another area that tends to overheat and melt connections is at the heater blower motor resister. Just examine all connections visually and clean them as noted. Loose and dirty connections create heat that can melt connectors and wires before blowing fuses and links. By far the worst problems are idiots that hack harnesses and do sloppy repairs.

 

I had the rear wire harness 5-wire connector that connects to the intermediate harness (located in the left side trunk under the quarter panel) completely melt and fuse together. I replaced the entire rear harness, as well as the terminals and connector on the intermediate harness. This on a '70 that has been garaged since '79.