Radio wiring etc

[Tinkley]

The Auto has the radio wired in to come on with the ignition, but I haven't looked where or how - yet. I have a number of minor electrical issues such as only part heat rear screen?, which I suspect is an earth issue and possibly related. Is it likely the earth on the steering column and/or the connector down near the heater block is less than good? The car is good for lack of corrosion, and the main earths on g/box and strap seem OK and clean. I assume the rear screen is earthed on rear n/s behind the light, as there are 2 or 3 leads going in there.

Where is the logical place to break into the ignition switch loom to wire in the radio as permanent 'On'? I'd quite like to return it to standard wiring, simply personal preference. Tracing this should help get to the bottom of these minor gremlins....

[kernowtim]

there should be a permanent 12v feed in the wiring loom going to the radio, even it the radio is wired to come on with the ignition there should also be a permanent feed for the memory/time on the radio unless its an old one with mechanical buttons for station selection

[Tinkley]

It's a replaced radio (Sony with CD player!) not the original Blaupunkt (I have a couple of those.. ) and although I am aware of the feed that would normally be the radio one, I have no dimmer rheostat or wiring to it! I suspect this has been diverted to become the radio on with ignition. Might also explain why I had to change half the bulbs in the dash whilst fitting a new speedo cable....
I thought there was always a feed to the original radio as it will work with ignition key out and off, just on the turn knob. That was even the case n my '88 Sharp radio (rubbish) on the 14. I just have the Sony unit unclipped in case I flatten the battery inadvertantly, at least for the moment.

[mat_fenwick]

Originally, as you state, there is no ignition switched feed to the radio, so it could have been taken from anywhere. I chose to take both the illumination wiring, and a switched supply from the (digital) clock.

What do you mean by part heat rear screen? Can't see how an earth issue would affect it other than a high resistance earth making it heat up less.

[Tinkley]

Originally, as you state, there is no ignition switched feed to the radio, so it could have been taken from anywhere. I chose to take both the illumination wiring, and a switched supply from the (digital) clock.

What do you mean by part heat rear screen? Can't see how an earth issue would affect it other than a high resistance earth making it heat up less.

Thanks Mat. I noticed the clock had one feed I think tappped into, there was a chocolate block there prior to feed into clock with two wires covered in black insulation tape. One obviously feeds on to the clock + the other single connection. I'll have a good poke around, as I have to sort the rheostat on the fan, which I got working OK but it has become intermittent (along with heat!, hopefully just total flush out), thanks to the tech stuff on here I'll try the 2nd earth point, and for the heater not sure if I need to dismantle the tap yet as I really do not want to risk breaking anything or causing a leak afterwards. Quite OK dropping the column etc but removing the n/a heater hoses could be fun....
Vanny's write up is pretty good.

On the rear screen heat, you got it, it seems less powerful than it should be, I'll clean up the earth. Even a relatively clean car can have issues when they are this old.... and this car is 'new' to me so I have yet to learn it's quirks.