Author Topic: Radio wiring  (Read 461 times)

balimatharu

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Radio wiring
« on: February 17, 2021, 17:49:16 »
I read some of the older forums but I am not sure about the wiring the radio.
In the radio area there is a black wire which is permanently live. Not sure if this was used to power the radio.
There are sources to get switched live.
I couldn’t find any source to get power at no.1 on the ignition switch.
None of the terminals on the fuse box gives power in position 1.
There are no extra wires around CSD.
Any suggestions where to get this power from, without cutting open the loom.
Or is it ok to use permanent live. I could put inline fuse as required.
Is there any device that is powered at no.1 position.
Any suggestions would be appreciated.
Bali

Pawel66

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Re: Radio wiring
« Reply #1 on: February 17, 2021, 19:19:40 »
As I was studying this topic and committed a lengthy post about it, let me perhaps suggest:

1. The factory way of connecting the radio is to look for black/red wire in the harness in the area of CSV/Regulator/coolant tank support. You would need to feel the harness a bit, untie insulation or cut it a bit - chances are the wire with voltage when key is in accessory position (black/red) as well as permanently powered wire for automatic antenna (red) are there. You will not see them there unless you open the harness a bit and extract them.

2. If not, you can have it any way you want:
a) radio can be operated with key in accessory position (as factory) - there is a pin R in the ignition switch, you need to find it. You will not find this position of key in the fuse box (I think). You need to have this wire go through auxiliary fuse box, placed next to the regulator. It is a single black/red wire in the ignition switch.

b) radio can be operated any time - you can take the power form fuse 1 (permanent power). I would take it from the supply side and have it go through auxiliary fuse box (e.g. the one next to regulator or the one next to brake booster support, if not used, or any other, e.g. in-line fuse solution). There are pros and cons of this solution - you can listen to the radio anytime you want, but you may leave it on accidentally...

c) radio can be operated when ignition is on - then you start from fuse 2 for example and run the wire through an auxiliary fuse box.

Automatic antenna should be powered at all times.

I am not sure about the black live wire...

The above is based mainly on 280SL experience.
« Last Edit: February 17, 2021, 20:08:48 by Pawel66 »
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

lpeterssen

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Re: Radio wiring
« Reply #2 on: February 18, 2021, 11:05:22 »
Dear Balimatharu

Some more ideas apart from the ones explained by my friend Pawel.

1. Right way and OEM way is: install an auxiliary fuse box on the engine Bay Area next to the CSV (cold start valve) take the feed side of the auxiliary fuse box connected to a RED/GREEN cable that is where Pawel said slightly folded on the harness next to the CSV connections(not red/black, that is mistaken). Run a Black cable trough the firewall to the radio. There are some rubber caps on the passenger side next to wiper motor.  This cable Red/green comes from the ignition tumbler switch, port labeled “R”

2. This black cable that you just inserted trough the firewall to the area where the radio will be installed is a switched hot source will be active when ignition switch on the “R” position, which I believe is something between “0” position and “1” position. All I know is that this position will not energize the ignition coil which is all the engineers had in mind to avoid damaging the ignition system while listening to the radio with engine off.

If you plan to listen to the radio only when the car is running, you can avoid all this hassle and take the energy from fuse no.3, which in most cars is not used and free.

Best regards
L.peterssen

balimatharu

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Re: Radio wiring
« Reply #3 on: February 18, 2021, 12:38:47 »
Thanks Pawel
Mine is 250sl RHD. I had a look at the wiring loom. Most of it is hidden under the brake booster.
I think I will go for switched live from fuse no.2.
My car has gone through almost nut and bolt restoration. Full body panel restoration, wings inner wings. Complete full back end.
Originally had a manual aerial at the left back corner. I was thinking of not making a hole for the aerial instead have a some sort of internal aerial for now.
It is going for full reupholstering booked for April. I will send an aerial, permanent live and a switched live cables from front to the boot for later use. Will that be enough?
I bought a new old becker europa kurier on eBay from Lithuania.
Back of the radio black cable will take power.
Also there is a spade connector with 2 terminals. One of them is marked +ve. I assume this connects the radio to the electric aerial. Keeping this in mind how many cables should be sent to the boot area.
Please advice.
One out of context question. My car is silver and black interior. I don’t particularly want to put black leather. I think your car is also silver but with red leather. What colours leather would be acceptable and would look nice.
Couple of photos of my car

Bali

Pawel66

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Re: Radio wiring
« Reply #4 on: February 18, 2021, 15:15:57 »
Your car would look beautiful!

Mine is 180, but with dark. Blue interior, upholstery code 245.

As for the antenna - you need permanent power there and the signal wire from the radio. Ground as well, of course.

Wiring the radio - i am afraid to advise anything, i do it by a hit and run method.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

balimatharu

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Re: Radio wiring
« Reply #5 on: February 18, 2021, 16:11:45 »
Pawel. Thank you

johnk

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Re: Radio wiring
« Reply #6 on: February 18, 2021, 17:45:16 »
wow! Impressive rebuild. Still amazes me the talent to reconstruct the body like that.
John Krystowski
Avon Ohio
1968 Euro 280sl under restoration
2016 Jag F-Type R
1950 Alfa Romeo 6C 2500 SS
2008 E350
2007 GL 450

balimatharu

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Re: Radio wiring
« Reply #7 on: February 18, 2021, 18:22:14 »
John don’t get impressed. It wasn’t me in my garage. I had to get it done by a body shop who specialise in classic cars.

lpeterssen

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Re: Radio wiring
« Reply #8 on: February 20, 2021, 11:30:36 »
Dear Bali

To the trunk you should send two cables, the third will come from a ground taken locally near the power antenna connection. 

1. Constant 12v which is called a T30 connection (fused). Take it from fuse no.1 at main fuse box and use an inline fuse just after in a place that can be serviced.
2. A trigger signal from the back of your radio. Locate the only single port that is behind it with a spade connector. Take photos and send to me per regular email.
3. The ground already mentioned before taken on the trunk itself on the already existent ground post.

The cable 1) should be RED size awg16
The trigger cable should be BLUE size awg 18. Not smaller since can be broken on the cable routing, nevertheless the power consumption will be minimal.
ground in BROWN, awg 16 as well.

Best regards
L.peterssen

balimatharu

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Re: Radio wiring
« Reply #9 on: February 22, 2021, 14:33:26 »
Peterssen.
Back of the radio has two spade terminals. One is marked as +ve. See the photo attached. I think it is for the automatic aerial. But there are 2 terminals.   
The second picture shows the wiring as I could understand from the post. Will this work.
Only issue is the 2 spade terminals
 Thanks.
Bali

balimatharu

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Re: Radio wiring
« Reply #10 on: February 22, 2021, 14:35:32 »
Pawel. Thanks for your feed back.

lpeterssen

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Re: Radio wiring
« Reply #11 on: February 23, 2021, 11:47:19 »
Dear Bali

Yes your drawing with the electric schematic is correct. You got our instructions right.

Regarding the spade connectors on the back of your radio. Not sure. One I see is labeled “+” and the other I can tell.

Which model is your radio to make a search on internet and confirm what is correct?

I guess you have a din connection between your radio and an external amplifier..... because I do not see speaker output connections there...


Best regards
L.peterssen

FGN59

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Re: Radio wiring
« Reply #12 on: February 23, 2021, 12:03:42 »
Not sure this will help, but you never know...

I have a Becker Europa II Stereo, with a closely related wiring scheme (see picture):

- the black wire coming out of a round black plastic hole with a red dot is for the power to the unit (far right, middle height)
- the black wire coming out of a rectangular black plastic hole is the antenna trigger (next to the left of power wire, bottom of unit)
- the two similar black and white round connectors arranged in a vertical line are for the speakers

Hope this helps
François

1969 280SL US specs, 4-speed manual, beige-grey (726H), parchment leather
1994 Toyota Land Cruiser SW HDJ80 4.2L diesel
1955 Massey Ferguson TEF20 diesel tractor 😁
sold:
1962 Jaguar MK2 3.8L (4.2L XJ6 engine), black, tan leather interior
1968 Peugeot 204 roadster, white, black interior

balimatharu

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Re: Radio wiring
« Reply #13 on: February 23, 2021, 13:29:53 »
Francois. Thanks for the replying.
You are right. Mine is mono so only one speaker outlet. Yours is stereo.
The spade outlet has to be the aerial trigger.
Thanks all for the help.
Bali