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HOW-TO: SC300/SC400 Install Aftermarket Head Unit, OEM Speakers and Sub Working!
#526
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Join Date: Sep 2014
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Amazing work my friend
I did everything as you described and boom, sound is back to my car, all 4 speakers working, antenna is working. I just have one issue wit the SW, I get power to the socket just once, I connected and power is gone and I don't know what to do after that, wires connected the right way, can I power the SW amp from another source? Besides that I love having sound back to my 1992 SC400, I'm ready to sell it and just need it this thing fixed.
#527
I did everything as you described and boom, sound is back to my car, all 4 speakers working, antenna is working. I just have one issue wit the SW, I get power to the socket just once, I connected and power is gone and I don't know what to do after that, wires connected the right way, can I power the SW amp from another source? Besides that I love having sound back to my 1992 SC400, I'm ready to sell it and just need it this thing fixed.
#528
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NOTE 3: As for the ground at A11, I’ve read that this works for some people, whereas others grounded the head unit directly to the chassis. I elected to ground my head unit to one of the chassis bolts found on the transmission tunnel directly below where the radio sits, using the crimp-ring listed in the parts list above. If A11 works for you, great! If not, crimp a ring and ground your head unit to the chassis.
NOTE 3: As for the ground at A11, I’ve read that this works for some people, whereas others grounded the head unit directly to the chassis. I elected to ground my head unit to one of the chassis bolts found on the transmission tunnel directly below where the radio sits, using the crimp-ring listed in the parts list above. If A11 works for you, great! If not, crimp a ring and ground your head unit to the chassis.
If the stock amplifier is bypassed but the sub-woofer is retained, then the signal grounds to the sub-woofer are left floating. That's probably not catastrophic, but it never hurts to keep the electrical grounds as designed by the manufacturer.
BTW... great write-up Raine. I have additional contributions I'd like to forward via PM once I'm finished. I'll leave up to you to include them or not. After all, you paved the way with some great content here.
Thanks,
-scott
Last edited by motorheaddown; 12-27-14 at 08:33 AM.
#529
The OEM head unit grounds will only work if the stock amplifier is retained. It is the "pass-through" for the head-unit grounds. Additionally, it provides the shielded signal grounds for the low-level inputs to the amplifier and sub-woofer amp. If you bypass the amplifier next to the CD changer, then simply jumper amplifier connector pin B7 to pins A10 and A11 (per Lexus Wiring Diagram), and you'll have OEM grounds going to the head unit.
If the stock amplifier is bypassed but the sub-woofer is retained, then the signal grounds to the sub-woofer are left floating. That's probably not catastrophic, but it never hurts to keep the electrical grounds as designed by the manufacturer.
BTW... great write-up Raine. I have additional contributions I'd like to forward via PM once I'm finished. I'll leave up to you to include them or not. After all, you paved the way with some great content here.
Thanks,
-scott
If the stock amplifier is bypassed but the sub-woofer is retained, then the signal grounds to the sub-woofer are left floating. That's probably not catastrophic, but it never hurts to keep the electrical grounds as designed by the manufacturer.
BTW... great write-up Raine. I have additional contributions I'd like to forward via PM once I'm finished. I'll leave up to you to include them or not. After all, you paved the way with some great content here.
Thanks,
-scott
Thanks,
-scott
#530
Driver
iTrader: (1)
First, thanks so much to raine. I started with the Metra, experienced a hum with everything off and alternator whine with everything on.
I almost pulled the trigger on the filters, but decided to do it the right way thanks to the great info in this thread. I'll still use part of the 70-8112 so I don't have to mangle the stock harness (A), but be sure to ground it to the body. I'll also be using the AMP+ wire here to trigger the woofer amplifier instead of running it.
I've also bought 2 x 70-1761 harnesses. I'll use part of one for the D1/D5 connection. The other, I'll use on the output harness (F) for the speaker connections. My HU has two sub pre-amp outs. Was going to use a Y into speaker cables and splice positives to D5 and negatives to D1. Is this acceptable? I noticed that you taped off your extra out...
I agree here with ISFFUN. My HU doesn't have an antenna out. I can't logically wrap my brain around why jumpering the ACC and B+ with the AMP+ will make a difference in antenna operation. I don't think I'm going to touch section I unless I have to as the woofer amplifier will be getting its AMP+ from A1 while ACC and B+ are already basically direct to the amplifier. However, I reserve the right to tuck my tail and fall back to the methods described here.
Thanks again, raine!
I almost pulled the trigger on the filters, but decided to do it the right way thanks to the great info in this thread. I'll still use part of the 70-8112 so I don't have to mangle the stock harness (A), but be sure to ground it to the body. I'll also be using the AMP+ wire here to trigger the woofer amplifier instead of running it.
I've also bought 2 x 70-1761 harnesses. I'll use part of one for the D1/D5 connection. The other, I'll use on the output harness (F) for the speaker connections. My HU has two sub pre-amp outs. Was going to use a Y into speaker cables and splice positives to D5 and negatives to D1. Is this acceptable? I noticed that you taped off your extra out...
I follow your logic, but there's no communication between the head unit and the factory amp. It's just a line out that's on for all sources. It (the aftermarket headunit) doesn't turn the amp (blue/white wire) power off when I go to CD. It doesn't have a blue antenna wire AND a blue/white remote power- only a remote power.
Thanks again, raine!
#531
I agree here with ISFFUN. My HU doesn't have an antenna out. I can't logically wrap my brain around why jumpering the ACC and B+ with the AMP+ will make a difference in antenna operation. I don't think I'm going to touch section I unless I have to as the woofer amplifier will be getting its AMP+ from A1 while ACC and B+ are already basically direct to the amplifier. However, I reserve the right to tuck my tail and fall back to the methods described here.
Thanks again, raine!
Thanks again, raine!
Apparently, most of the newer head units don't have an "Antenna" output; my pioneer HU is the same way. I still wanted the antenna to function when only running the radio, and the best I could come up with is to use a PAC TR-7 (http://www.pac-audio.com/PACProductD...ons_010505.pdf) as a latched relay (Feature #3). Once programmed, you can use OEM on/off switch to manually raise/lower the antenna since power on/off is already handled by the aftermarket HU. I had to route power to the OEM on/off switch which is used as a momentary input to the TR-7 where it is "latched". Then, you'll simply raise/lower the antenna when you need it using the OEM on/off button, but at least it's not up all the time when the head unit is turned on.
Thanks,
-scott
#533
You can have your cake and eat it too.
-scott
#536
It should still work. The on/off switch is simply a momentary switch that is now disconnected from the OEM head unit; so, it's normally open. With the relay latch enabled through the on/off bottom, I see anywhere from 0 to 20k ohms based on the position of the dial.
You can have your cake and eat it too.
-scott
You can have your cake and eat it too.
-scott
#537
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Join Date: Feb 2015
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After market double din deck factory sub and amp
Hi I recently changed to a double din and changed my rear speakers to 6.5 my sub n amp don't work anymore I was wondering if I can use my factory sub n amp
#540
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Join Date: Feb 2015
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Any way of doing this without running the new speakers wires back? Someone way of using the existing wiring? I dont care too much about the sub. But I'm just wanting to get my radio working quickly until I can figure out all the stuff I want to do.(I currently have no headunit cept some $25 amazon special I just got)