Where to buy parts online

Good afternoon Guru's! I was wondering if anyone could recommend a good place to buy parts online. In the near future I'll be buying an engine harness for my truck and I've yet to find a website that can beat what the dealership if offering for the part. The dealer wants $565.54 for the part (+tax). Most of my search results are about that amount. If I could find a site that sells it for $500(+shipping) or less I'd be a happy camper. You might ask "But it's only $65 - man up!", and you'd be right. But I'd like to establish a source for future needs. It might be a $65 premium today, but I'd like to avoid FUTURE part premiums as those can add up over the course of a year. Any help in this regard would be greatly appreciated. Thx

 

I've checked out ebay. Low prices for an engine harness but I didn't see one that matched the part number I had. A general "Detroit Series 60 engine harness" yielded the most results, but like a said, I didn't see my exact part number :'(

 

The part number I was given from the dealership is A06-47470-000 but all the harnesses I saw on ebay follow a 235XXXXX format. And the other site suggested didn't yield any results either

 

Crap. Lol my dealer doesn't give out part #'s - company policy. They want us to buy parts from them. I'll try calling other dealerships and hopefully I'll be able to find one that will. Thanks for the suggestion

 

I've done that already. All they give me is the dealership part number. Even on the printed receipt it list only the dealer part #. I have half of a mind to buy the thing from them and HOPE to get the number that way, and then return it for a refund.