Factory amp bypass necessary? (2 Viewers)

[flintknapper]

Here's one thought, why not hook it up leaving the amp in play and see how you like it. It doesn't take much time and won't cost you anything. If you aren't impressed with the sound (like I was), then you can work more on the bypass version. I've got the bypass instructions for the LX 450. If you want them, I can scan and send them to you. They're at home, so probably can't get them to you until tomorrow.


Rookie2

Edit: Those harnesses look alot like the ones I got. FYI, all the wires don't get hooked up.

Thanks Rookie,

Pretty sure I want to bypass the amp (based on what others have said). Some folks have gone with the factory amp., but not many.

Just looking at the harness...I don't see me using the brown (mute) wire or the blue (antenna) wire. Not sure about any others until I get in there.

Thanks for the info.

 

[SMG1]

I've got the same issue I think and I can't find where it's been resolved on other post. I am trying to install a new head unit in place of the factory radio because mine quit working in my 96 LX450. I bought the wiring harness that Best Buy suggested for a vehicle with a factory amp. I think I've got it wired correctly but it won't turn on. Does the power go thru the amp first? It's been a while since the factory radio worked but if I remember correctly, it would turn on for a few seconds, then blow the fuse. Now if I plug in the factory radio, it does nothing. Could it be the amp? I'd really appreciate it if you guys could lend some advise!

 

[Qball]

Just went through the same thing. Yes delete the stupid amp, it was problematic and sounded bad.

You just need the standard toyota harness and extend then 16 inches to your head unit and problem solved. Took no more than half an hour and everything works great. If you have a LX then factory sub won't work, but it never added anything anyways.

 

[1973Guppie]

I disconnected the dash speakers and simply plugged in the crutch field harness, sounds great. I don't think it is necessary to not hook up the factory amp


...via IH8MUD app

 

[David Samuels]

I know this is an old, old thread. I've been unable to find any good schematics on this 15 pin setup. Where are the grounds for the four speaker, no amp system? Found the hots, and a diagram that confirms them in the plug. We also have s-gnd and gnd, but no lines that are clearly from the speakers for the negs. Where are they connected? Thanks.

 

[Qball]

Yes!

 

[David Samuels]

"Yes", it's an old thread? Ha!

 

[1973Guppie]

I know this is an old, old thread. I've been unable to find any good schematics on this 15 pin setup. Where are the grounds for the four speaker, no amp system? Found the hots, and a diagram that confirms them in the plug. We also have s-gnd and gnd, but no lines that are clearly from the speakers for the negs. Where are they connected? Thanks.

just buy one of the conversion HU harnesses for your vehicle model and year, it is dead simple, everything is labeled and all you have to do it wire it up to the HU harness, then plug it all in, this conversion harness uses all the factory plugs for power etc.

 

[-Spike-]

I know this is an old, old thread. I've been unable to find any good schematics on this 15 pin setup. Where are the grounds for the four speaker, no amp system? Found the hots, and a diagram that confirms them in the plug. We also have s-gnd and gnd, but no lines that are clearly from the speakers for the negs. Where are they connected? Thanks.

IIRC they use a common ground, probably s-gnd (speaker ground?).

 

[Malleus]

There's a common ground, inside the harness:

FWIW, the Metra pigtails supplied by Crutchfield have these covered:

I removed the leads in the two white connectors, attached new terminals to the ends of the leads from the black head unit connector, and inserted them into the white connectors. This not only reduces the amount of wire volume behind the head unit, but it completely removes the bullet connector splice which is necessary when you use the material as supplied.

 

[Lummie]

I know this is a pretty old thread but I just replaced my Metra harness from Crutchfield with the Scosche Harness and my stereo sounds like a whole new system! I've been driving around with tinny audio the last 7 years! Wish I had done this years ago.

 

[Malleus]

So what did you do, cut off the OEM harness connector and replace it with a handful of bullet connectors?

 

[Lummie]

So what did you do, cut off the OEM harness connector and replace it with a handful of bullet connectors?

I removed the Metra harness and connected the Scosche harnesses to the harness that came with the headunit. Plug the new harness into the grey connectors behind where the headunit sits. Then unplug the factory amp that's located behind the glove box. After that you're done.

 

[BuckarooBanzai]

@Lummie thanks for the recommendation! I just finished swapping in the new Scosche harness and the stereo sounds great!

Do yourself a favor and get this harness. I think it’s like $7 on Amazon. Great upgrade!

 

[Irish Reiver]

Whats the difference between the 2 harnesses.. they look and do identical functions or have i missed something?

 

[BuckarooBanzai]

I can’t explain it in technical terms but when you remove the metra harness and connect the new Scosche harness, you will plug into a different connector on the truck side. There are three factory looking plugs when you remove the radio and the Scosche will plug into two of the three and not use the one that the metra harness used. You will also not use the RCA connectors with the Scosche harness.

 

[Malleus]

One set (pair) of OEM harness side connectors includes the OEM amp, the third (single) connector doesn't.

 

[ppc]

The OEM setup that incorporates the OEM amplifier is a single white connector. The pair of grey connectors bypass the factory amp. If not used, the connection at the factory amp should be disconnected or the amp removed.

 

[Malleus]

...or that