Hey, I'm currently trying to hook up a modern head unit (93 camry) to my corona, there's a bit of wiring involved to get it to work properly.

The original corona radio plugs are a 3 pin(speakers I assume) and a 2 pin(gnd and acc(12v)).

My query is: does the new h/u need acc AND batt(+) AND gnd to operate, or can I just use batt AND gnd?

Any help appreciated

-Long

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Choosing an old car doesn't have to mean you're on your own. JNC

No you need all three, otherwise with just battery and Gnd it will be power on even when you take the key out, and can drain your battery if you accidentally leave it on.

With just Acc and Gnd and you will loose presets once ignitions turned off.

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Thanks Redsunday,
At the moment I'm taking +ve from the lighter (can't remember if the lighter was acc or batt now) I'm assuming it was acc, do you know a good place to take batt(+) from? Or should I just run a line right to the battery?

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Choosing an old car doesn't have to mean you're on your own. JNC

just run it straight from your fuse block but just add another fuse.. or is the Sig lighter is 12v constant (12v+ Bat) you can run it from her since the cig lighter is fused.. as for the acc 12+v you can just run it straight from the ignition switch...

Yes, the cig lighter is fused so I'm running 12v const from that, How do I run the 12V acc from the ignition? any pictures and such? I'm a noob at this.
Also, by taking it from the ignition switch, does it affect anything? (ie. current division)

_________________
Choosing an old car doesn't have to mean you're on your own. JNC

Ok,
Final piece of the puzzle is finding the best spot to connect 12V acc to.
I ran 12V acc from the +ve connection of the radio fuse but the head unit seems to be pulsing which is wierd (all the interior lights pulse on aswell).

Can someone tell me how to wire up acc properly? Any help appreciated

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Choosing an old car doesn't have to mean you're on your own. JNC

Ok the pulsing aunt good.. You can use the ACC 12v but you need to unplug the original head unit, also it would be best for you to run a new ground to the frame and not from the original wireing. Ps. If you get engine whine you can install a filter on the 12v batt side or just run a wire straight from the batt... Hope it helps

Hey Arsonist,
Yes, I have unplugged the original unit, I've also tried a different grounding point and also a direct line to the battery, but I still get the weird pulsing

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Choosing an old car doesn't have to mean you're on your own. JNC

Wires I have:



Alternative GND point:



Where I've taken ACC:






Boots up with wierd pulsing, still no sound yet with speakers and antenna plugged in

_________________
Choosing an old car doesn't have to mean you're on your own. JNC

Oh ok hmm... Have you tested the new head unit straight at the bat. (benched tested the unit) before installing it. If it still pulses when bench testing it the unit I bad. Also try grounding the units metal shell to ground (just to make sure you have the right ground wire from the plug), onother thing you can't use the commen ground setup most old units use (meaning 1 neg. Is shared between 2 speakers) so you will have to run new quering to all the speakers. If your using the comeb ground set up with the new unit it will cause the pulsing thing you have going on. Hope this helps you out...

Oh thanks for that arsonist, I think that head unit was dodgy.

I found out what the problem was, I connected ACC to the wrong side of the fuse, it works fine now.

A question though, does anyone know how to extend the antenna wiring?

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Choosing an old car doesn't have to mean you're on your own. JNC

koo that its working now ....
as for the antenna issue you can buy extensions or do it the poor mans way and chop and extend, ether with ordinary wire or use coaxial cable (cable TV cable or video cable)

hahaha, yeh, i intend on doing it the poor mans way since I ripped antenna cabling from another corona. I just have to figure out how to join coaxial cables together

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Choosing an old car doesn't have to mean you're on your own. JNC

Crimp/solder/tape the middle wire together and do the same for the wrapping wire and finish it up by wrapping the 2 cable with tape to give the one wire look..... (electrical tape)

Awesome, thanks a bunch!

_________________
Choosing an old car doesn't have to mean you're on your own. JNC

HELP!
After I installed the h/u, now my tail lamp fuse keeps blowing! I'm suspecting a short somewhere but I want to verify that the new h/u isn't the cause.

Here is a summary of everything I changed:

-Cut/Taken 12v batt from the cig lighter
-Unplugged original h/u
-Taken -ve/GND from the original h/u
-Taken ACC directly from the fuse box (after the fuse)

Fuse keeps blowing even though I unplug the new h/u

_________________
Choosing an old car doesn't have to mean you're on your own. JNC

theirs a caution that need to be taken.. you said you got the ground from the old head unit.. you have to make sure that its a true ground and not a tricky ground. what i mean by tricky ground it that it shows ground but will turn positive when the lights turn on (illumination).. (it common. im not crazy).. thats why they say ground to frame...