I am looking to disconnect the factory hk sub and put an aftermarket under rear seat. I want to use the factory amp. I wondered if anyone knows the impedance of the factory sub. I don't want to fry my amp.
2019 Ram 1500 Laramie. U connect 12" with Harmon Karson System.
I've been out of the car audio game professionally for about 12 years now, so I'm going off of my knowledge from then, not sure how much factory amplified systems have changed since then. With that being said, we would never connect an aftermarket sub to a factory amplifier for multiple reasons.
1: Usually factory speaker resistance is much higher than aftermarket. I've seen factory stuff range from 8 all the way to 16ohms, while most aftermarket is 2-4 ohms. Yes you could wire 2 4ohm subs in series and make it an 8ohm load, but that brings me to the next reason...
2: Your factory amp isn't going to be anywhere near powerful enough to push most aftermarket Subs. While it will probably make it "Play" the lack of power to drive it will make the upgrade pretty much not even noticeable, if not make it sound even worse than it did stock.
3: This one is probably the most important... It WILL void your warranty! If anything does happen to the sound system, amp - speakers- radio - ect, regardless if its because of the aftermarket upgrades or not, the dealer will blame it on that... and good luck trying to prove them wrong!
I had the last issue with a jeep that had aftermarket amp/speakers installed (factory amp bypassed) The radio went bad in it (the radio still functioned but the screen wouldn't come on). The dealer tried blaming it on the aftermarket equipment saying it was causing the radio to overheat. After arguing with them they finally agreed to replace it "This once" and acted as if they were doing me a huge favor.