Author Topic: Radio connection.  (Read 4975 times)

Larry & Norma

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Radio connection.
« on: May 18, 2010, 14:59:47 »
Hi, my 1970 280SL has a modern radio which will only work with the ignition in the engine running position. The wiring diagram tells me that there is a facility to
run a radio from ignition switch position 1. The wire from the switch should be coloured red/green. I cannot find the fabled 2 fuse box so assume there is not one.
I do not want to take the dash apart again just yet, so does this red/green wire go anywhere and is tied out of the way?
Thanks
Larry Hall (Gnuface)
2023 Ioniq6
2005 C230
1970 280SL

al_lieffring

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Re: Radio connection.
« Reply #1 on: May 18, 2010, 15:08:02 »
the fuse box should be on the right inner fender by the shock tower and voltage regulator. If you can't find this the terminal onthe switch for the accesory power #1 position is labeled "R" on the back of the key switch assembly.

Naj ✝︎

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Re: Radio connection.
« Reply #2 on: May 18, 2010, 16:48:31 »
Hi, Larry,

Mine is a '68 and does not have a fuse box but I did find the red/green wire sticking out of the wiring loom on the right near the shock tower as Al indicated. It is live when the key is at position 1.

naj
68 280SL

Larry & Norma

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Re: Radio connection.
« Reply #3 on: May 18, 2010, 17:12:44 »
Well done Naj, I have found the wire taped up in the loom as you said by the shock tower. Great!
There is another red/green wire in the loom, do you think it might be the return from the (not present) fuse box and reappears behind the radio somewhere?
Could it be that simple!! Hope to investigate tomorrow.
Larry Hall (Gnuface)
2023 Ioniq6
2005 C230
1970 280SL

Naj ✝︎

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Re: Radio connection.
« Reply #4 on: May 18, 2010, 21:53:08 »
Hi, Larry,

Mine is a manual and has just that one wire.

I noticed one one pic I have that the wire on the CSS on autos also has the same colour wire?

naj
68 280SL

Larry & Norma

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Re: Radio connection.
« Reply #5 on: May 19, 2010, 12:48:15 »
FYI i found a red wire next to the red/green wire. Both these wires had about 1cm stripped and tinned then an insulating cover placed over before being taped into the loom.
The red wire is permanently live. So perhaps the red/green is to power the radio in ignition position 1 whilst the red wire is for keeping the radio memory live. Was this type
of radio around in 1970? Nevertheless a useful find!
I hope to wire my new radio ( Custom Autosound USA-4DIN ) this weekend if it arrives!
Larry Hall (Gnuface)
2023 Ioniq6
2005 C230
1970 280SL

al_lieffring

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Re: Radio connection.
« Reply #6 on: May 19, 2010, 13:37:12 »
The live all the time wire would have been used to power a motor antenna.

Naj ✝︎

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Re: Radio connection.
« Reply #7 on: May 19, 2010, 14:43:25 »
Larry,

On RHD cars the voltage reg is mounted forward of the shock tower.

There are two holes rearward of the tower where the reg on LHD cars would be fitted.

May be you want to add a fuse box there?
68 280SL