Stereo wiring question

[SanRafaelFaz]

So, as I was "dry fitting" my upper and lower consoles last night, I went to listen to some tunes before fastening everything in place. No power from the radio. Nothing, no pretty lights, no indication of life.
Background: The unit was in the car for several years with no problems at all. When I pulled the old consoles, I took the radio out and put it away until about a month ago when I plugged it in and it worked fine (not "installed" just kind of lying on the floor). As I was shoving the upper into place I apparently knocked out a short thin yellow wire which is now hanging from the radio harness. It has a tag on it which reads "Memory: Connect to hot lead". I have no idea where it came from, nor if this is what caused the radio to play dead.
Any advice?
TIA!

[dantye]

So, as I was "dry fitting" my upper and lower consoles last night, I went to listen to some tunes before fastening everything in place. No power from the radio. Nothing, no pretty lights, no indication of life.
Background: The unit was in the car for several years with no problems at all. When I pulled the old consoles, I took the radio out and put it away until about a month ago when I plugged it in and it worked fine (not "installed" just kind of lying on the floor). As I was shoving the upper into place I apparently knocked out a short thin yellow wire which is now hanging from the radio harness. It has a tag on it which reads "Memory: Connect to hot lead". I have no idea where it came from, nor if this is what caused the radio to play dead.
Any advice?
TIA!

A blown fuse is a possibility, what with the rats nest of wires moving around. The radio plugs are also notorious for one or two pins not quite connecting, and sometimes need a little push with a tiny screwdriver to assure that they connect. If you can, find a manual for the radio on-line. (I'm assuming it is not an original). Then check the yellow lead to see if it is about 12volts to ground all the time. even if the Ignition is off. If so, the yellow wire probably provides the "memory" voltage that allows your radio to electronically maintain all of the pre-set station buttons when the radio is off, but that alone should not keep the radio from operating. It should be re-connected wherever it came loose. That's the fun part.
Hope this isn't too confusing and will help.

[TX82FIAT]

Most stereos have three wires you need to have right. Red for power, yellow for memory/aux and black for ground. The solid colors (POS) and stripes (NEG) correspond to speakers. I think testing the wires for ignition on power and constant power is the starting point. The sterios have been wired and re-wired over the years so your colors may or may not match up with diagrams or standards.

[bradartigue]

FIAT's wiring harness has no "MEMORY" line marked. There is exactly one connector for the radio, it has four lines for the speaker (L+/L-/R+/R-), one +12V switched, and one ground. There are, on Spider 2000's, two power antenna leads (Blue/Red and Blue/White). The "memory" concept of digital radios was never put into the cars, so you pull constant +12V from the lamp lead (yellow/black I think) or cigarette lighter.

You can get the right plug to adapt your radio to the FIAT plug, and use all the stock wiring, from Auto Ricambi, i'm pretty sure I saw it there yesterday.

[dantye]

FIAT's wiring harness has no "MEMORY" line marked. There is exactly one connector for the radio, it has four lines for the speaker (L+/L-/R+/R-), one +12V switched, and one ground. There are, on Spider 2000's, two power antenna leads (Blue/Red and Blue/White). The "memory" concept of digital radios was never put into the cars, so you pull constant +12V from the lamp lead (yellow/black I think) or cigarette lighter.

You can get the right plug to adapt your radio to the FIAT plug, and use all the stock wiring, from Auto Ricambi, i'm pretty sure I saw it there yesterday.

It is good to know about that plug. But there is no telling what a PO may have changed. This is all I had to go on, and had to figure it out with a meter:

[bradartigue]

But there is no telling what a PO may have changed.

Sure there is, use a wiring diagram to find the original source wires, remove everything the PO did, start over and do it right. In your case your car appears to have had factory (really dealer-installed Panasonic radios or in some cases FIAT branded radios) radio. I say that because both sides of the radio plug have the correct wires and colors. That's about as good as it gets.

My personal favorite radio was the one a PO had in a 79 Spider and had wired the illumination to the hazard switch somehow. The radio lights worked but (probably due to the weird grounds on a FIAT) pulsed when the blinkers or hazards were on.

On the 82 I currently am working on the PO used none of the factory wire and ran all his own, creating a mess everywhere. Luckily though it left the stock wires intact.

[dantye]

But there is no telling what a PO may have changed.

Sure there is, use a wiring diagram to find the original source wires, remove everything the PO did, start over and do it right. In your case your car appears to have had factory (really dealer-installed Panasonic radios or in some cases FIAT branded radios) radio. I say that because both sides of the radio plug have the correct wires and colors. That's about as good as it gets.

My personal favorite radio was the one a PO had in a 79 Spider and had wired the illumination to the hazard switch somehow. The radio lights worked but (probably due to the weird grounds on a FIAT) pulsed when the blinkers or hazards were on.

On the 82 I currently am working on the PO used none of the factory wire and ran all his own, creating a mess everywhere. Luckily though it left the stock wires intact.

I stand corrected. Speaking of Hazard blinker, I had to wedge that red button in with a thin piece of plastic until I can get in and, hopefully fix the stop "spring", and learned that you have to position it just right or your turn signals won't work. Since this button seems to be a common problem, I thought I should post it and maybe someone will read this and avoid an accident!