any tips and tricks for splicing into old brittle wiring?, need to replace the wiring to the tail light switch Options

[bradtho]

first thing first, I've tested the reverse light system and the switch works fine. If I squeeze the snapped wires together I can get the backup lights to turn on.

So I need to replace a section of this harness. I've used a solder iron before and had success, but its not like I really know what I'm doing.

1) I'm going to need to remove the pin connectors and put them on my replacement wires. I'm assuming I can separate them from the old wires reasonably easy with a normal solder iron and simple re-solder to new wires. anything else I should expect here? My understanding is these pins are NLA, so want to make sure I don't ruin my good existing set.

2) the wire is pretty stiff all the way back to the engine tin. I'm hoping to replace as little as possible, maybe start with just 2in and see if I can get it working. Is that a bad plan since it's likely to break again? the wires inside the engine comp aren't nearly as stiff. I'd like to keep the existing harness. solder? butt splice?

Is this a losing battle with 40 yr old wires?

[wingnut86]

Replace the harness unless you like skydiving without a chute;-)

Email Jeff Bowlsby here on TheWorld to see if he can supply some of what you need if not all...

[Tom]

bradtho,
Do you have the wires that need replacing? A grey/brown and a green/red about 6 ft. or so. Maybe a little longer. It would be simple to remove the 12 pin connector and completely replace the wires from the connector to the switch. If you want to come over to Port Orchard, I have the tools needed to help you get this done. If you are not concerned with the color codes, I have some red 14 ga. that would work OK. Are the bullet pins at the switch soldered or crimped? If soldered, no problem. Crimped could be hard to save. I think mine were soldered, but that was 6 years ago. CRS setting in! (IMG:style_emoticons/default/sad.gif)
Tom

[toolguy]

You can get the correct color of wire from a wrecked 914 wiring harness or someone on here is sure to have a few feet of what you need. . I keep a box full of old Porsche wiring and have spliced out old wire before. . . . . the wire is usually only hard where it has been exposed to the heat of the exhaust. . . the "bullet' ends are soldered on and can be removed and reused. . . get a new rubber cover for the switch before you start. . Often the older copper wire is hard to get solder to stick. . . scrape the wire with a knife edge to expose fresh copper, and be sure to use soldering flux. . . l I found plastic covering identical to original at a surplus electronic shop. . use that and some shrink tub and it will look just like OE. . .

[bradtho]

I hadn't considered trying to partially replace the harness. I don't have the right color wires, which is why I was thinking of just butt splicing in the minimal necessary for the fix.

I'll likely install a 6 in a couple years so dropping the coin on one of bowlsby's fancy harness' seems like a bit of a waste at this point.

not sure how this is like skydiving w/o a chute. I wouldn't consider the backup lights to be that serious.

[bradtho]

thanks toolguy, exactly what I was looking for. so if I splice in, do I need to work all the way back down the wire until it isn't stiff? or is anywhere fine as long as I avoid bending it?

the rubber boot is in great shape, so I'm good there.

[nathansnathan]

I have been fondling my wiring harness recently. I patched the 72 harness which was damaged prtty badly with the 71 parts car's which was fairly brutalized.

I find crimp on to be crap. All of the worst parts of the 71 had crimp ons instead of the good stuff. I would rather solder on a wire connected to a stock connector than do the connectors myself, but if I do, I like to use the noble soder on connectors with heat shrink as insulation - I think the factory did them that way on the hot leads.

Where the wires are exposed at the ends gets a bit dry. I rubbed them with glycerin. It cleans up the stickiness from the loom tape and softens the ones that aren't too far gone. Too far means they have cracked. It helps to slowly bend the wires as you're rubbing them. It sort of opens up the pours. At worst, you get some whitness where the brittle insulation stretches, but if you are holding the wire in a paper towel soaked it glycerin, it is magically healed as that happens. (IMG:style_emoticons/default/biggrin.gif) It works well for the plastic protective sleeves too.

I got some 3M 1755 cloth electrical/friction tape and cut it to size using an exacto blade clamped to lathe. Heat shrink tubing. (IMG:style_emoticons/default/aktion035.gif) Wiring diagrams are on the bird site.

[IronHillRestorations]

Clean up the harness before you do anything.

Stair step your splices so your harness won't have a big pregnant bulge in one spot.

Solder and double heat shrink. Just be sure to put the heat shrink on before you solder. Read up on correct soldering techniques so you don't end up with a cold solder joint.

Double check your completed work with an ohm meter to make sure all is correct before putting into service.

You can help stiff brittle wires into submission with gentle use of a heat gun, just take care as you can do damage if you aren't careful.

Silicone spray helps get wires through grommets.