Radio power lead query

[njoconnor]

On the modern replacement radios I've seen, there are two power leads: one to constant (non-switched) power, the other to switched power (ACCY ON). The constant power lead on the Retrosound I bought has its own 15 amp fuse. The switched power, none.

1) Does the switched power lead just operate a relay inside the radio, to "switch on" the radio when the car is running/in ACCY position?

2) Anyone have an idea of the amp draw through these switched leads? I'm thinking of tapping into one of the switched leads coming away from the fuse block, but don't want to overload the circuit.

Thanks. Radio and door cards are about all that's left. Thne picture time. I promise.

Neil

[azruss]

the power draw is radio specific. You need to look at the spec sheet in the owners manual or on line. Like most modern electronics, they are on all the time in a sleep mode. That way when you turn it on, it doesnt take 5 minute to get going. Your Fiat has a fused circuit for a radio. It will handle anything except some over-the-top high amp system. Also, be aware that with the radio constantly on, it will create an amp draw that will eventually drain the battery.

[njoconnor]

Thanks!. I dug back into the specs, manual and on line, and it appears the switched lead draws minimal power. I also picked up an in line fuse holder, and will tap into a lead upstream from the fuse block. That ought to keep everything happy.

I'm not sure the early (circa 72) cars had a dedicated lead for the radio; neither of the wiring diagrams in the original owners manual shows anything like that. But...I'm still learning to read these things, so another session over a beer might help.

Thanks again!

Neil

[bradartigue]

Thanks!. I dug back into the specs, manual and on line, and it appears the switched lead draws minimal power. I also picked up an in line fuse holder, and will tap into a lead upstream from the fuse block. That ought to keep everything happy.

I'm not sure the early (circa 72) cars had a dedicated lead for the radio; neither of the wiring diagrams in the original owners manual shows anything like that. But...I'm still learning to read these things, so another session over a beer might help.

Thanks again!

Neil

Interestingly enough the early Spiders had radio wiring (radio and speakers or speaker) but not in the diagrams because the radio wasn't stock. At the time the diagrams were specific to the components FIAT supplied with the car in Europe. Supplements covered the radio and USA (or regional) differences (e.g. emissions control equipment) when fitted. In 1974 the diagrams changed to following the circuits themselves, meaning some had no component (e.g. radio) on the diagram.

[njoconnor]

So....if my 72 has radio wiring, what locations and colors might I look for? Still in the preinstall phase, so I could easily use the stock radio power leads if they are there.

Brad, I've really appreciated your collecting and clarifying the various years' wiring diagrams. If you'd like to add scans of original 72 diagrams ( European and North American), pm me with the format youd prefer and I'll get working on them.

Thanks

Neil

[MrWampus]

The un-switched power lead for your radio is a low-draw lead that powers the radio's clock and the preset memory for radio stations. The switched power lead powers the radio when it is switched on. If your car has no radio power lines, you can draw the unswitched power from your clock circuit and the main power from just about anywhere else. I tapped into the door chime circuit on my 81 so I could turn on the radio just by inserting the key in the ignition without actually turning the key. I did this because I did not want to run my fuel pump and charge the coil just to listen to the radio. That method has worked well for me.

[bradartigue]

So....if my 72 has radio wiring, what locations and colors might I look for? Still in the preinstall phase, so I could easily use the stock radio power leads if they are there.

Brad, I've really appreciated your collecting and clarifying the various years' wiring diagrams. If you'd like to add scans of original 72 diagrams ( European and North American), pm me with the format youd prefer and I'll get working on them.

Thanks

Neil

Unless someone removed it there is a connector in the radio console for it, and there is most likely a factory installed speaker as well.

[njoconnor]

Thanks, Brad. Yeah, someone moved those leads (and the speaker!). I found two leads coming off the ignition switch, and using good crimped taps, connected the radio leads with their own inline fuses. Also added good crimped disconnects for future maintenance/upgrades! Works nicely...now to figure out all the settings on the radio!

Neil