RA23 electrical questions. Disaster aversion post.

[masterofsinanju]

Folks, I'm looking to wire up a head unit and while I think I have this figured, my knowledge of electricity and circuits is limited to yr11-12 physics.

I'm comfortable that I need to tap into 12V from one of the always on circuits like the cigarette lighter for retaining settings within the unit and power from one of the ign/acc (in this case the radio) for the actual power on function.

I'd thought to take them from the back of the fuse box and just run new wires to the head unit. I would think I need to make sure that these wires must be after the fuse to make sure that any problems cause the fuse to blow. On the back of the fuse panel there appear to be two thicker wires at each end that I guess to be where power goes in and then the fuse box spreads this out for power to go the the various components. My thoughts are that I'd de-pin the relevant plug and fit a double blade connector (thanks Stitt).

Some pics below might better explain what I'm considering.

This one is the right hand side of the fuse box and you can see the thicker blue with black stripe as a stand alone plug. My thought is that I need to de-pin the white plug and tap power from the thinner blue wire (this is the radio wire)


This is the left hand side of the fuse box and I think if I de-pin and take power from the second red wire from the left in the black plug (this is the cigarette lighter power) I'm on the right track.


This last pic is the wiring from the head unit and while it is clear that the red wire is the power wire and the yellow wire is the memory/settings power wire, there is also something labelled "illum" and I have NFI what this is for other than something to do with illumination (maybe dim the display when headlights go on?) and whether or not I need to power this one.


I'd already been to an auto electrician and asked for them to label the appropriate wires for what I need only to return at the end of the day to a $200 invoice and instructions to buy the right sort of plug to just "plug it in". WTF? There is no such fucking plug in my harness, hence my need to label appropriate wires to hook into. So, I'm hoping to figure this without causing a conflagration.

[caam]

Hi, yes splice into those two wires for constant and ignition/acc wires to the red and yellow.
And you're bang on with the illumination, dims the headunit with your headlights, I haven't ever bothered hooking them up

Edit most stereos have an inbuilt fuse, have a look on the back of the headunit

Cam

[masterofsinanju]

Thanks Cam, yeah 10 amp in the back of the unit but I'm more worried about screwing something up on the car side of things and having an unplanned car warming party.

I won't be hooking up the illum wire then. Shits me to have the display dim when I have headlights on during the day.

[lexsmaz]

Sounds like you got ripped something stupid by the Auto Electrician i hope you didnt pay or certainly got a discount ??

[allencr]

'illumi' dash lights, not headlights.

[TheStitt]

First pic. does the three pin plug come straight from the ignition barrel? From the wiring diagrams I've just looked at I think it does.

to prove this pull the 3 pin plug off, get your multi meter, set on voltage (20v) but the red into the blue/black and your multi's black wire to earth and you should see 12v with the key in ACC and IGG


If this proves true. the single plug, blue with black trace should be over a 5amp fuse and be going to the radio. You wouldn't have to de pin, just use the double adaptor plugs I set you the link to, or if your aren't planning on powering the old radio, just pull that wire off the fuse box leave it hang there and sort an insulated terminal and crimp to new wire and run straight to new Head unit.


the second pic, the big white is constant power and comes in one side of the fuse box and powers several different circuits. One is the plain red (no trace) to your ciggy lighter. Would you could do here is de pin the ciggy terminal from the main plug cut the terminal off, then get another wire and crimp a new terminal on with both wires together. put new terminal into main plug and you should be wining.

as allencr said, if you do want illumination you would run that from dash lights.

the wire colours are similar to the crowns, just sucks that the celicas use big plugs like that, the Crown just has single plugs coming off the back of the fuse box, so it makes it really easy to double adapt.



I used Jeffro's post for wiring diagrams

http://www.toymods.org.au/forums/tec...g-diagram.html

[masterofsinanju]

So I knocked it over today (well at least the part where I know it all works as intended). Wires that I could get enough reach on, got solder. Wires that were just too damn short got connectors and heatshrink. I'll also update my thread, but thought I'd finish it here in case some other clueless individual might benefit from pictures.

Thanks for the heads up on the piggy back connectors Stitt, makes for a lot neater.



So the initial intent was to de-pin the plugs but all things being equal, I would have needed to ditch the white plug and the black plug and then reconnect everything, including the wires I didn't want to splice into. Also, I tried for like an entire minute or so to get one pin out. So I took the simple way out as seen below. (to be honest, the piggy back connector wouldn't have fit on the back of the fuse box, so cutting the wire and rejoining seemed reasonable)



So this is just where I ran leads for the constant power and switchable power. When I can get to jaycar I'll grab some wire that matches the loom. I hate that there are changing colours and I'm sure it flies in the face of all sorts of electrical best practice. However, today was when I had the time and I had red and blue wire on hand.

Also noticed that the wiring for the conversion (the in cabin stuff at least) remains highly visible on the pax side and the ground point is right in the footwell. Has been added to the list of things that function but really need to be tidied up.

I've still to sort out mounting the head unit and working out where the front speakers will go. Trying to avoid the door as I don't want to cut the cards. May try the kick panels (only 4" speakers).