Can somebody advise me on the wiring for the Antenna pre-amp? I'm putting a new stereo in that is ISO connection, and I'm not sure what to connect the pre-amp wire (little red wire) to, is this a power or is it something else? Much appreciated Adrian
Interesting. The 348 wiring diagrams don't even show a red wire. Here's a comparison between the 348 and 355... Image Unavailable, Please Login How many pins does the radio plug have?
It’s for my 355. The radio is an iso connector as below. So I’m unsure what the antenna amp wire #7 would go to. Is #7 just a power source for the amp or something else? Image Unavailable, Please Login
oops.. must have looked at your profile pic. The pin numbering in the wiring diagrams doesn't match up to yours, so I'd say the antenna pre-amp probably just needs a switched 12 volts supply. So... I guess a splice on A7. A5 might not be suitable, especially if the polarity reverses.
Thanks Ian, That’s what I thought. The antenna pre amp wire does have an inline fuse so should be fine. It doesn’t seem to make a huge amount of difference anyway! I do however just have the single power to the radio at the moment, number 3 pin. Just now figuring out why I have power to the radio and the side lights are on without the ignition being on, I think there is a relay in the passenger door well that looks like it maybe at the centre of this...more investigation required!
Sounds familiar... Did you mention this earlier? Did you simply push the park light switch on the centre console by mistake? That operates on battery power.
how stupid do I feel!!!? Didn’t even know what that button did. Thank you, that saved an embarrassing fault hunt!!!!
Connect Permanent +12V supply to A4 - this keeps +12V always supplied to the radio to maintain its memory Connect Ignition Switched +12V supply to A7 - this energises the radio when the ignition is switched "on" Connect Antenna Preamp wire to A5 - this is "12V" output from the radio which provides signal to activate the antenna motor (in the case of such type, to raise the telescopic antenna), a signal to activate a separate sound amplifier (if used) or to power the antenna preamp; this output is present only when the radio plays (and not present if you play a cassette or a CD).
How can A5 perform all 3 functions, Miro? Wouldn't an antenna motor need different polarity voltages (which would only be required when the antenna goes up and down?) Does the "pre-amp" (or some other box handle antenna extension/retraction) and there is a separate power source for lowering the antenna when the voltage on A5 disappears? Or are you saying A5 only performs one function in this case? (e.g. by pin programming)
12V output from A5 has limited current, usually ~500 mA. It operates the antenna motor relay which usually takes less than 100 mA. The relay switches-over the polarity of the antenna motor so relay "on", antenna goes up; relay "off", antenna is retracted. As the antenna preamp probably takes ~10 mA, it can be powered directly by A5. In this way, the preamp will be powered only when the radio is "on". If the preamp is wired to the Ign. switched supply, it will be powered all the time when the engine is running which is not necessary. So, A5 is not good to be used as power supply for anything that requires more than ~500 mA. It cannot be used as the main power supply to a separate sound amplifier but it can be used for its "turn-on" line which takes some 20 mA or less (the main sound amp power supply is a separate permanent 12V supply). On some radios, the signal like from A5 is only present when you listen to the radio (goes off when a CD or cassette is inserted/activated, antenna goes down); on some radios the "A5" signal is present all the time with the radio "on" irrespective of whether you select radio, CD or cassette (in which case it can also be used to turn-on the sound amplifier) and on some radios there is a separate sound amplifier turn-on output.
