1998 LC Aftermarket HU WIRING

[PabloCruise]

Additionally, all of my work is 100% reversible. I could revert it to stock in a single evening, save the single small hole for the power wire in the firewall. Not a single wire was cut in my entire process.

I am going to have to go back and watch how you accomplished this - it has great appeal!

 

[LBridges]

Additionally, all of my work is 100% reversible. I could revert it to stock in a single evening, save the single small hole for the power wire in the firewall. Not a single wire was cut in my entire process.

Good on you. Would love to see how you did that. My approach for the LC would be to use a metra headunit harness and a couple of Scotch Lock Quick Splices at the amp. I think that removing all the amp plugs then using the aftermarket headunit high level outputs spliced into the output side of the amp would about cover it. If the LC is like the LX, one would have to find switched power someplace for the headunit, but that could be a double scotch splice with a jumper between the gray in and out wires on the amp wiring plugs. This is only because the switched (ACC) power runs to the amp first in the Nak system on the LX. Maybe Toyota turned the amp on first to ensure no turn on "pops"?

 

[suprarx7nut]

I can shoot to be over at 9. Removing the seat is dependent if you want to bypass the amp or use the factory amp. I know using the harness gave you a hiss and most insist it cannot be done but in two installs now I have been able to use the factory amp and have zero his/pop etc by not using the harness and tying in the low level outs from the new head unit directly to the inputs to the stock amp. Most harnesses try to pass the high level speaker outs from the headunit as a signal for the amp which causes the hiss and pop issue since an already amped signal is being amped again causing the distortion. Maybe the LC is different than the two LX's I have done but I am willing to give that a go if you would like. If you prefer to just bypass the factory amp its easy also but pulling the seat would help as the last time I did that without removing the seat I left half my knuckles behind. Maybe give me a call if you can so we can get our ducks in a row before Friday.

I *think* you're going to find the LC to be a different beast. When doing mine, I used the low level speaker RCAs and tried tying into the amp ground. It didn't help. If you try it though, please let us know. I'm curious if anyone's been able to get a 98-99 LC to work well without the amp bypass. I'm pretty confident the answer is "no", but the more data points, the better.

I am going to have to go back and watch how you accomplished this - it has great appeal!

Buy a terminal extractor and a new 090 style connector and it's cake (assuming you also have a decent open barrel crimper)

Good on you. Would love to see how you did that. My approach for the LC would be to use a metra headunit harness and a couple of Scotch Lock Quick Splices at the amp. I think that removing all the amp plugs then using the aftermarket headunit high level outputs spliced into the output side of the amp would about cover it. If the LC is like the LX, one would have to find switched power someplace for the headunit, but that could be a double scotch splice with a jumper between the gray in and out wires on the amp wiring plugs. This is only because the switched (ACC) power runs to the amp first in the Nak system on the LX. Maybe Toyota turned the amp on first to ensure no turn on "pops"?

I've used a few varieties of the Scotch lock splices (some run parallel, some perpendicular). Some work well, some do not. Personally, I'll never use them again if I can help it. Their performance in the best case scenario is worse than nearly any other method of connection (solder, crimp, twist and tape, twist and wire nut, etc...). The only thing they have going for them is that they're easy to install - incredibly easy.

You're close for the power solution. For the switched power you just need to tie the two ends together at the amp and use the corresponding lead in the metra harness. The switched power normally goes into the amp, then out to the deck. Just connect the two ends at the amp and you've got switched power up at the deck. I used a second connector to achieve that "jumper" of sorts because the terminals don't mate (female and female, i believe). If you're ok with cutting OEM wires it's all very easy. If you're a little anal like me, it's still not too bad!

 

[Emcd]

I'm willing to cut, modify, Cobb together any solution to make this sound as good as the investment I've made in the new HU and speakers!

 

[Ali FJ80]

I *think* you're going to find the LC to be a different beast. When doing mine, I used the low level speaker RCAs and tried tying into the amp ground. It didn't help. If you try it though, please let us know. I'm curious if anyone's been able to get a 98-99 LC to work well without the amp bypass. I'm pretty confident the answer is "no", but the more data points, the better.

thanks for the heads up, if the LC is that different then maybe we will skip this part and just go with the bypass.

@Emcd maybe you do want to remove the front seat and do you have the wire diagrams for the plugs at the amp. We will just need to know the speaker outputs going from the amp to the individual speakers.

 

[Emcd]

I have the seat removed, the diagrams and everything we need but a barrel crimping tool.

 

[ITRJ]

I haven't read all the replies here so forgive me if I'm repeating info. I just installed a pioneer in my 98LX with factory amp and no sound quality issues. I will post a thread on the process but it's fairly straight forward. The speaker lines between the HU and AMP are pre out signals so you must use the pre outs on the head unit (RCA's). The RCA's in you metra harness occupies 4 pins in the connector, 4 speaker + and 1 speaker - . You need to connect the 4 speaker + from the harness to the first 4 pins, and tie all 4 speaker grounds into the 5th pin. Then connect the RCAs to the pre outs in your head unit.

 

[PabloCruise]

I haven't read all the replies here so forgive me if I'm repeating info. I just installed a pioneer in my 98LX with factory amp and no sound quality issues. I will post a thread on the process but it's fairly straight forward. The speaker lines between the HU and AMP are pre out signals so you must use the pre outs on the head unit (RCA's). The RCA's in you metra harness occupies 4 pins in the connector, 4 speaker + and 1 speaker - . You need to connect the 4 speaker + from the harness to the first 4 pins, and tie all 4 speaker grounds into the 5th pin. Then connect the RCAs to the pre outs in your head unit.

Did your '98 LX have the Nakamichi head unit and amp?

Thanks!

 

[ITRJ]

It's a Lexus premium. Made by Fugitsu. But this method should work for any amp

 

[Emcd]

This forum and it's members never ceases to amaze me. A huge heartfelt thank you to Ali FJ80 for coming over this morning to help me bypass the factory amp. The system sounds like I hoped it would. 100000x better than before. All the diagrams provided on this forum made this a one banana job. Thanks for all the help!

 

[Ali FJ80]

Anytime. This forum has helped me so much it was the least I could do.

@PabloCruise seems you are somewhat close so if you need a hand when you get around to doing yours be happy to help also.

 

[PabloCruise]

Anytime. This forum has helped me so much it was the least I could do.

@PabloCruise seems you are somewhat close so if you need a hand when you get around to doing yours be happy to help also.

Thanks! I am up by Fort Collins, but I would really like to update the LX! I'll PM you some digits.