Please Help, Wiring Problems for 74 Spider

[dkunce]

A few days ago my ignition switch died on me. Not a new thing, it has happened twice before. The 15 pin on the back of the ignition switch got so hot it melted some of the back of the switch and burned part of the pink wire. I got to talking to a mechanic at Vick Autosports and he suggested I test to see if the pin was definitively dead. I did and also found that there was a short to ground in the pink wire somewhere. My question is how I would go about locating and resolving this problem. I assume because the pink wire is grounding out that its drawing too many amps and therefore causing the ignition switch to fail? I'm no expert at all and any advice would be greatly appreciated. On top of that not too much of the wiring in my car matches the wiring diagram in my Haynes Manual. It doesn't appear that there are wires spliced in or many signs of "shoddy" wiring repair, it just doesn't seem to match. I am struggling with this. I've removed my dash, pulled my wiring out enough for it to be easily accessible and have visually checked everything I have access to. To this point nothing seems to be frayed or noticeably damaged. I replaced the fuel pump (it had seen better days and I had a brand new one to take its place) I removed what seemed like miles of black "electrician's" tape from the wiring harness, and inspected my connectors. I've gone about tidying things up to the best of my ability. Also, I've noticed a green/black wire that was routed to my ignition switch. I've read elsewhere here on the forum that it could either go to the fuel pump relay, or to the fuel pump directly meaning it was hot wired to the ignition switch. Where would I locate the fuel pump relay to see if it is still installed in the vehicle, and how would I go about reinstalling this wire properly? Sorry for the length of this post, I'm honestly at a loss here and its a real head-scratcher.

~Dustin from Shreveport

[RRoller123]

There are a bunch of posts on this problem, and the most common solution seems to be that Spider owners put most of the heavy current draw items, like head lights, wipers, radiator fan, etc. on relays, pulling power for them from the Alternator directly and offloading the ignition switch in the process. Try a search on the topic of "Relays" and a lot of posts should come up

[dkunce]

I'd like to say there are a few relays (4-5) installed...they look much older, so maybe not on any of the high draw systems, but I'll look into installing new relays for headlights and the like. as far as the short is concerned, any advice?

[RRoller123]

sorry that one is beyond my knowledge

[dkunce]

Thanks for the suggestion. I'm looking into pricing for relay kits. Would you say the best way to wire those in would be to take input from the B+ on the ignition coil to the high side of the relay and wire the switching side of the relay to the power that was originally run to the peripherals (head lamps, washer motor, etc.)? Or should the high voltage side of the relay be powered form the alternator?

[DocGraphics]

IAP has a premade relay conversion for the headlights,pretty much plug & play.

http://www.international-auto.com/headl ... e-kits.cfm

Also for adding relays the power should come off the alternator, not the coil which would tax voltage going to the ignition & is supplied thru the ign switch.

[dkunce]

Ok, still having issues resolving the short in the system. I replaced the 10g wire that comes from the ignition switch on pin 15. It was the one registering the short. It plugged into #9 on the fuse panel. It was fine, there was another smaller pink wire that shared a connection with the larger, it is still shorting to ground. Does anyone know what it goes to? I've reconnected my ignition switch and the car will not start. The starter motor, engine fan, gauges, and everything seems to be working properly, but it will not start. Any advice? At this point I'm feeling tempted to pull the entire wiring harness and inspect every wire, I know its dramatic, but I'm at a loss. There aren't exactly any Fiat specialists located less than 200 miles from me. I need as much help as possible here, I'm not too sure what I should do. This is my first car and my first restoration project.

[RRoller123]

This is from a 1979 schematic, so can't say it works for your car, but it shows the pink wire going from the ignition switch and to the coil. You could try checking along these lines for shorts, etc. It is a little blurry, but the pink goes to Fuse #1, "A".