Originally Posted by Joni4TA
I just went through all this!! Got the new head unit in no prob, without the 3rd plug.. but getting the factory amp/sub to fire up some bass was a whole different ballgame! I had my other half out there with a voltmeter checking all kinds of stuff... we had to go to Radio Shack and get some kind of resistor too... it took him the better part of ohhhhh let's be liberal and say 8 hours lol
I'm sorry, I have no good advice to give. It's a major pain in the rear to hook up an aftermarket head unit to the factory amp/sub is all I can say. But it can be done! I'll see if I can ask the old ball and chain exactly what he did, and providing he actually remembers I will get back to you.
I share your frustration though!
It is definitely very frustrating, I have pretty much everything ready to drop into my dash except this third plug garbage. Here's hoping your SO remembers what all it took to get you up and running.
I debated buying a busted 9006 on ebay and ripping it apart to cut the female connector off the circuit board and basically making my own adapter for it. If there isn't an adapter produced to accomplish what I want from someone like Metra I will probably end up going that route.
I have an unnatural aversion to permanently altering factory equipment like that third plug. I'm one of those "exactly as it came from the factory or as close to it as possible" kind of guys. This car came with an aftermarket alarm system installed and ripping that mess out is on my short list of things to do.