Morris Minor Owners Club

So I have just passed my test and bought got my first car a morris minor. I have been searching the web on how to wire a car radio but all i seem to find is how to install one in the glove box. It is now installed and i was wondering if anyone could help as im not quite sure where the power wires are supposed to go.

Thank You

James

1st of all is your car +ve or -ve earth (which battery terminal is connected to the bodywork)

if you know what wires are which on the radio its not too hard..... my +ve comes from the green wire coming off the ignition barrel, and my -ve is from earth. My car is negative earth.

If your car is posative earth make sure the radio wont touch any bodywork, because it is probably set up for negative earth, and reverse the polarities i have mentioned

Probably about to be told what I hal told you is a load of codswallop....

As Matt says it is essential that you know if the car is pos or neg
earth. Very few radios are suitable for use on positive earth cars.
If you take your live feed from the fuse with white wires on one side
and plain green on the other then the radio will only work with the
ignition on. If you want it to work without ignition on then take the
live feed from the fuse with brown wires on one side and purple on
the other. If you find that your car is still positive earth it is probably
better to follow the instructions in 'Technical Tips' on this site on how
to convert to negative earth. The other half of the radio power
supply is,of course, connected to the metal chassis.

Ok i have converted the car to negative earth very simple using the technical tips page thank you. However the wiring of the radio is still confussing me. I need a bit more help. As far as i can see there are 3 wires to be connected

1. Battery
2. Ignition switch (B+)
3. Ground

However where abouts on the car are each three supposed to go. I take it that ground can just be attatched to the body. Then the other 2???

The ground wire goes somewhere on the bodywork
feed the wires through the bulkhead to the fusebox, the battery one should clip on to the fuse with brown/purple wires. The ignition one should go on the other fuse

(thanks kevin )

To follow on from Matt, I prefer to be able to use the radio without ignition on e.g. if stopped for a while.
On my car I connected the "battery" and switched feed together to an unswitched supply. As far as I know the battery connection is a constant supply for retaining presets and other user defined functions.

my radio requires both...... it will only switch on with the ignition on, but it needs the permenant connection for the presets...

That's right Matt it will if your radio supply is fed from a separate switched source. As are probably most others.
Both are fed from an unswitched permanent supply on mine for the reason given.

Don't forget that on modern cars, it is usual that the radio will only run with the "ignition on". This is actually a misnomer, as the ignition does not need to be on - the Accessory position (or Pos. I on some cars) runs the electrics. If you wire your radio into the ignition you will have to energise the whole system just to listen to music. There is a remote possibility (can't see how, actually, but it could be possible) that you could burn out the coil &c. by having a charge running through them for any length of time without the engine running. Also it would increase battery drain.

GARETH it is absolutely CERTAIN that you will burn out a coil if
you leave the ignition on for a long period without the engine
running. If the engine is at rest then the dizzy contacts are closed,
this provides a through path for the 12v supply to go through the
coil winding- through the points- and straight to earth. The coil
winding will overheat and .....Kaput!

JIMMYCHUCKLES.......If you are still confused then join your
two +V wires together as suggested. These would normally pass
through an in-line fuse emerging from the radio, if that is so then
in order for the radio to work at any time you wish connect the
+V lead to the left hand fuse on the side with the BROWN wire on it.
If there is NOT an in-line fuse then connect the +V lead to the same
fuse but on the side with two PURPLE wires on it. The 'GROUND'
wire goes to any part of the metal body.

Thanks for that, Willie. I thought I was right... glad I've got a stereo with an 'on/off' switch on it so it's not ignition controlled!

Willie wrote:GARETH it is absolutely CERTAIN that you will burn out a coil if
you leave the ignition on for a long period without the engine
running.

That's why I prefer an unswitched supply on a Minor.

Yes, that's the reason mine is unswitched too.

it is absolutely CERTAIN that you will burn out a coil if
you leave the ignition on for a long period without the engine
running.

If anyone doesn't believe Willie, turn on the ignition and put your hand on the coil. Within a few minutes it will get too hot to touch....

I've wired up the power supply to the radio (not the "always on" preset power supply) via a separate rocker switch under the dash.
That's because the internal aerial needs a power supply to the amplifier. I'm cynical enough that I want to turn that off when I'm not using it! It also acts as a remote on/off for the glovebox radio...

Colin

The Radio I have in the landrover is great from the point of vew of the IGN/No IGN view. It's the bog standard Mercedes one that a flash friend had removed from his new car to make way for a "Super duper" radio.

It has some logic in so it remembers what state it was in last .. So if you had it on the last time you were driving it will come on with the ignition, if you turned it off it won't.

But the real genius is that if you turn the IGN off (the radio will turn off) then press the Power button it will turn on again and continue to run until a voltage threshold is reached then it will turn off.

In ref to polarity and position of battery i have noticed on my 65 model the terminals are close to the securing strap the recomended way for a - earth but is still a+ polarity any thoughts on that. FROM NEW BOY KEITH