I've been having starting issues for years. Sometimes she starts, sometimes all I get is one click from starter solenoid. Everything replaced - still have issue. But if I turn the key on, and put 12v+ directly to starter where purple wire connects, it cranks everytime. I also get 12v+ on the purple starter wire every time.

So I figured I'm dropping amperage on the purple starter wire betwen the neutral safety switch and the starter. But I didn't want to run a new wire from inside to outside (lazy). So, my mind tells me relay. A solenoid is basically a big relay. If I have my purple wire energize a relay that connects a wire directly from the battery to the starter solenoid (rather than me doing it with a 3ft chunk of wire), that should work. So I did it, and it seemed to work like a champ! Until ...

I press the hatch release button with key off - nothing happens. Now my hatch always works with key off. Check fuses, all good. For whatever reason, 5 minutes later I had key on, and press the hatch release button - the car starts!

OK - I know that the hatch release button is wired into the neutral safety switch, so that we can't accidentally pop the hatch at 100mph - hatch only works in park. But what I can't understand, is that the car never started by use of the hatch release button before, why would it do it now? Only thing I did was connect a relay under the hood to the starter signal wire so that rather than sending 12v to the starter, it sends 12v to the relay that THEN sends 12v to the starter.

So why won't this work? I'm guessing that the hatch release button would run the starter IF it had enough juice it could feed through the purple wire, but it never did, until now. With the relay in place, it takes very little power to activate the relay, and thus the hatch release button can now feed enough power to activate my relay and thus feed the starter battery power. That's my guess - what do you think?

Here's what I did:

 

Ok, so thinking about my theory, if I put a diode on the power wire that feeds the hatch release button, then that would allow the current to only travel TO the button, and not backfeed out of the button back to the neutral safety switch, right?

So, for you electronics genius's out there, what diode would I need? I know nothing about diodes, how they are measured/rated/etc.

 

bump for diode help...