So my factory head unit quit playing CD's, so I bought a Kenwood receiver from Crutchfield. I have not had a chance to start installing, just found out my factory system has an external amp. From everything I've read people say you can still use the factory amp, but how is this wired? Using the preamp outputs on the Kenwood? You wouldn't use the regular speaker connections, cascading two amps together would you? Crutchfield sent a wiring harness, I just glanced at it but it doesn't appear to be using the preamp RCA connections on teh Kenwood.

If it is not a PITA to bypass the external amp I may just do that, but I'm not sure the Kenwood would be work well with the 2 ohm factory speakers? I can do any tweaking I need to, but I'd rather keep this as plug and play as possible.

 

i have mine running through the factory amp. when you wire up the new radio you need to connect the amp turn on/ power ant wire( usally blue or blue/white) to the infinity anp turn on wire. im not sure what color off hand, but this has been dicussed on here before. do a search in the forum.

 

Same here. Mine runs through the Infinity amp just fine. I thought it would be a problem, but after almost 2 years it's still running just fine. Wire it normally and don't forget the aforementioned amp turn on connection or you'll have no sound out.

 

I have the manual so I'll figure out the amp turn on wire, I think it is green with orange stripe.

So running two amps in series is no problem? Hard to believe but ok, I guess it just runs with the volume lower to compensate? Thanks for the help guys.

 

The OEM Infinity amp remote on wire should be green/orange, sometimes to me it looks like it's green/red. Either way it's on the black speaker output plug in the OEM radio harness, at the very end of the plug. The harness Crutchfield sent you probably has a solid blue wire on it. Connect the blue/white wire from the new Kenwood deck to the solid blue (or blue/white if you have one) on the Crutchfield harness. This will trigger the OEM Infinity amp no matter which source you use, radio or CD.

The system will work and sound good with interfacing the high-level speaker outputs to the speaker level inputs on the OEM amp. The down side is you don't get much of a turn on the volume **** before the system gets loud in the truck. That is to say, with the volume level on the Kenwood at about 1/4 of the way up, the volume that you hear from the system will be about that of the factory radio at half to maybe 3/4 of its maximum volume level. This is due to the Kenwood having much more power in watts on its speaker outputs than the OEM radio had. It will still sound good though and should have better bass response than the factory radio.

It is possible to bypass the factory amp and wire the Kenwood directly to the speakers in the truck. If you look at the factory amplifier plugs you will see the same wire colors for the inputs to the amp as you have for the outputs from the amp to the speakers. The speaker output wires may be a bit larger gauge, and they may be twisted together in pairs. This is how you can identify which wire is which. Compare the speaker wires up at the factory radio harness to the corresponding wire colors on the Crutchfield harness to figure out which wire does what. For example, look at the solid green and green/black wires in the Crutchfield harness as it plugs into the OEM radio harness. This is going to tell you which 2 wires are the left rear + and - speaker wire inputs to the factory amp. Now find those 2 colors down at the amplifier location. There should be 2 sets of wires with the same colors that correspond to left rear up at the radio. Cut them, and connect a test speaker to one set, turn on the radio and if you hear music from the test speaker, you have identified the speaker level input from the radio side of the amp harness. Then the other 2 wires with those corresponding colors will be the speaker output wires that lead to the speaker itself. To test to be sure you have the speaker output wires, you can connect each wire to the one of the terminals on a 9 volt battery. It will make a popping/scratching sound from the speaker. If you want to bypass the factory amp, just connect the wires together, color for color. I don't know what year your truck is but if it's a 2000 or older, left rear + will be brown/yellow and I think left rear - is brown/blue. If you have a 2001 or newer truck, left rear + will be white/red and left rear - will be white/black. So on a 2001 or newer truck you would connect the 2 white/red wires together and the 2 white/black wires together to bypass the amp and connect the Kenwood deck directly to the factory left rear speaker without running any new wires. Do this for the other 3 speakers and then you will not be using the factory amp. It's a good idea to unplug the amp if you are not using it though.

The factory speakers in the truck should be 4 ohm and the Kenwood can handle them just fine. If the speakers are in bad shape, good replacements are not too expensive. I would say to try the Kenwood deck interfaced with the factory Infinity amp and see how you like it. Most people do like how it sounds that way.

Jimmy

 

Thanks for the info and reassurance on using the amps in series. Sounds like the volume will behave as I expected. I wonder if the input sensitivity of the amp is like most amps, i.e. why not just use adaptors with Kenwood's RCA preouts?

BTW, to help me decide one whether to bypass the factory amp, what do you guys think it compares with the amp section of this http://www.crutchfield.com/p_113KDC4...rand%7cKenwood ?

 

if your talkin about the 50 x4 watt built into the radio itself, then you will have no problems running it through the factory amp. mine haas a 100 x4 watt output and i still ran it through the amp. just use the wiring you got from crutchfield and you will be happy with it.

 

There used to be adapter interfaces that used the RCA jacks from an aftermarket radio and converted it down to a high level speaker wire input that plugged into the OEM radio harness. The problems with them were they cost a lot (back in the day they ran about $60.00), they were hard to adjust correctly, and they were noisy and personally I didn't think they were very reliable. I don't know if the adapter is still available. Like others here have suggested, just try the Kenwood connected to the factory amp, and see how you like the sound. If it's too much volume too soon for you, you can bypass the amplifier. Or maybe later add a good quality aftermarket 4 channel amp with new coaxials in the back and a good set of component speakers in the front doors.

Jimmy

 

They told me same thing, that it wouldn't work and if I replace the speakers to replace the amp or it won't work...well I did it otherwise and just hooked it up like normal and guess what. It worked lol

 

That worked with mine....for a while