New Headunit, Wiring Confusing Me

[ciarancassidy]

A few people seem to have been reporting this sort of thing, I wonder if there are some dodgy amp bypass cables being sold on eBay ?

i think it could be, i am gonna check all the wires later and see which one should be wired in

[ciarancassidy]

hey I was having a look at the wiring last night, trying to figure out the memory wire, there is 2 connections that come out of the back of the old headunit and then there is one wire on its own that connects to a wire that I cant see were it goes, could this wire on its own be the memory wire?

[Steviewevie]

It sounds like you might be describing the power feed to the aerial amplifier (goes off in the same direction as the aerial wire). This is actually a power feed coming *out* of the head unit, powering the aerial amplifier so that you can get radio reception, and is a black wire.

What year is your Lex ? The permanent 12V feed (i.e. to keep the memory going) on very early cars is a red wire coming out of the amp from pin 7 and going into the head unit on pin 1. This changed to a blue and yellow wire going into pin 1 on the head unit, from about mid-2000, as far as I can tell.

[ciarancassidy]

It sounds like you might be describing the power feed to the aerial amplifier (goes off in the same direction as the aerial wire). This is actually a power feed coming *out* of the head unit, powering the aerial amplifier so that you can get radio reception, and is a black wire.

What year is your Lex ? The permanent 12V feed (i.e. to keep the memory going) on very early cars is a red wire coming out of the amp from pin 1 and going into the head unit on pin 1. This changed to a blue and yellow wire going into pin 1 on the head unit, from about mid-2000, as far as I can tell.

Hey, yeah i was describing the aerial amplifier power cable, mine is a 2001 so it should be blue and yellow, will go have a look after work and hopefully that will be it sorted, also gonna wire up the dimming cable while i am at cause wow is it bright at night,

[Steviewevie]

ok, you need to make sure the aerial amp is still powered from your new head unit, so there should be a cable from the new head unit's harness to connect up to that, otherwise you will get very poor radio reception.

As for the power, yes, blue and yellow is what you need to look for on your model. That will be the permananent feed both to the amp and to the head unit in your OEM wiring.

For the illumination, I wired up the dimming wire on my new head unit's harness into a nearby green wire, see a thread on this subject here.

[ciarancassidy]

ok, you need to make sure the aerial amp is still powered from your new head unit, so there should be a cable from the new head unit's harness to connect up to that, otherwise you will get very poor radio reception.

As for the power, yes, blue and yellow is what you need to look for on your model. That will be the permananent feed both to the amp and to the head unit in your OEM wiring.

For the illumination, I wired up the dimming wire on my new head unit's harness into a nearby green wire, see a thread on this subject here.

ah great thanks, yeah there is a blue wire coming out of the new harness for that so will wire that up aswell, and thanks for the link to the thread, cant wait to get all this sorted, just need to finish off my fascia adaptor then and pop it on

[Steviewevie]

Post up some pics when you're done so we can see ! :D

[ciarancassidy]

Post up some pics when you're done so we can see ! :D

I will do indeed, this fascia is taking a lot of work to get it to fir propper, but hopefully looks good when I am all finished

[ciarancassidy]

hey so i am out sitting in my car at the moment trying to sort out this memory problem, have the blue and yellow wire, and also have the yellow wire and the red wire from the back of the radio, have tried a few different things but nothing is working, about to pull my hair out here :(

[Steviewevie]

Have you got a multimeter (or similar) where you can check which wires are giving you voltage ? Where have you found the blue and yellow wire, in the OEM wiring that used to go into the OEM head unit ? It would be good if you can verify that it's still powered up (it should be, it doesn't go to the now-disconnected amp like most of the other wires).

Does your new head unit instructions say which wire is the permanent 12V input ?

[Steviewevie]

ok, I downloaded the install instructions for your head unit, and that shows that it's the yellow wire that goes into the back of the head unit that needs the permanent live feed.

The illumination control wire appears to be an orange one with white stripe.

[ciarancassidy]

Have you got a multimeter (or similar) where you can check which wires are giving you voltage ? Where have you found the blue and yellow wire, in the OEM wiring that used to go into the OEM head unit ? It would be good if you can verify that it's still powered up (it should be, it doesn't go to the now-disconnected amp like most of the other wires).

Does your new head unit instructions say which wire is the permanent 12V input ?

hey yeah i got the blue and yellow from the oem wiring that went into the headunit, was actually thinking maybe it is dis connected, have a multimeter somewhere so will look for that now, the permanent 12v is the yellow wire and the red wire needs to go to an accesory terminal in the fuse block,

oh got the dimmer working though, thanks

[Steviewevie]

Is the red wire not already connected up ? That's your switched live feed, and is grey on the OEM wiring on your model year.

[ciarancassidy]

Is the red wire not already connected up ? That's your switched live feed, and is grey on the OEM wiring on your model year.

I had it wired up but when i was trying to figure out this current problem took it apart, in my amp bypass lead there was no were for the red wire to go, at the moment my wiring is a complete mess

[ciarancassidy]

at the moment have the red wire connected to the grey wire, which is switched live and have the yellow wire connected to the blue and yellow(constant live), turns on no problem, works away and all but doesnt hold the memory so now checking to see if the blue and yellow is getting power, in the amp by pass cable there is a yellow cable that has memory on it and even when i connect the yellow cable from the stereo to this it still doesnt hold the memory

[ciarancassidy]

hey i have checked every possible wire i could and I am not getting any power to the constant live at all, even tried plugging the amp back in and still nothing,

[Steviewevie]

How about if you plug the OEM stereo back in as well as the amp. Does it still work and hold its memory ?

Are you saying that you've used a multimeter and the amp bypass cable isn't giving you any constant live ?

Have you checked the cable that your amp bypass cable is plugged into, down by the amp, is that not giving constant live either ?

[ciarancassidy]

How about if you plug the OEM stereo back in as well as the amp. Does it still work and hold its memory ?

Are you saying that you've used a multimeter and the amp bypass cable isn't giving you any constant live ?

Have you checked the cable that your amp bypass cable is plugged into, down by the amp, is that not giving constant live either ?

hey yeah i'm not getting any constant live at all even from the cable the amp bypass is plugged into, it seems to be working just like a switched live, checked the grey wire aswell and this is switched live aswell, i was thinking this morning, does the clock have a constant live because it holds the time so could i splice my constant live in there?

[Steviewevie]

hey yeah i'm not getting any constant live at all even from the cable the amp bypass is plugged into, it seems to be working just like a switched live, checked the grey wire aswell and this is switched live aswell, i was thinking this morning, does the clock have a constant live because it holds the time so could i splice my constant live in there?

That's very odd.

Yes, the red and yellow wire into the clock is a permanent live.

[ciarancassidy]

hey yeah i'm not getting any constant live at all even from the cable the amp bypass is plugged into, it seems to be working just like a switched live, checked the grey wire aswell and this is switched live aswell, i was thinking this morning, does the clock have a constant live because it holds the time so could i splice my constant live in there?

That's very odd.

Yes, the red and yellow wire into the clock is a permanent live.

ah brilliant, I will try splicing in the yellow cable from the back of the new headunit to this cable when i get home and hopefully that will be it all sorted

[ciarancassidy]

have it all sorted finally, me and one of the lads in work were out pulling out fuses upon fuses and found a blown one, replaced it and the permanent live is working, radio is on all the time now, so need to just swap over the wires later :D

[Steviewevie]

Lol I didn't think about the fuses ! Was it the "Radio No. 1" fuse that had gone ? That's the one on the permanent live. That would explain a lot ! :D

[ciarancassidy]

Lol I didn't think about the fuses ! Was it the "Radio No. 1" fuse that had gone ? That's the one on the permanent live. That would explain a lot ! :D

i never thought about it earlier, was showing him the radio and told him about not getting power to the permanent live and first thing he asked was did i check the fuses, yeah it was Radio No. 1, felt like kicking myself, spent 3 hours last night checking all the wiring

but all good now :D

thanks for all the help Steve,

will be priming the fascia adaptor tonight :)

[Steviewevie]

Great news that you've sorted it ! :D

[ciarancassidy]

thanks a million again, will take some pics later of it in the car, and of how the fascia is coming along, it needed a lot of cutting and sanding to make it fit nice and snug :)