no..no.. cut the blue wire

spyderman · 10-13-2003, 07:00 AM

Need some help under my dash. I'm putting in a new CD player, and can't for the life of me figure out the wiring. Found the ground, verified that there is no power antennea, but I'm left with the main power wiring bundle. I know this, because that was what was plugged into the back of the old tape deck. There is a bundle with three wires. One is blue, and has it's own plug, then there is a black, and a red stripped white wire, that are splaced together into one plug. I get juice out of this last plug only when the key is turned on. No juice at either time on the blue one. The whole bundle leads up and into the ignition switch. As I said I found the ground (brown wire), but have not been able to figure out the rest. Anybody got any ideas?? 1970 T is the car in question.

spyderman · 10-13-2003, 08:13 AM

quack...

Vintage911Racer · 10-13-2003, 08:25 AM

Just run all new wires.

Ground, Power to battery for +12 volt power, One to fuse Panel for your Switched power. Put a test light on the fuse holders and turn the iginition on. Find one that lights up in the on position and connect there.

304065 · 10-13-2003, 09:15 AM

Those colors don't match the factory diagram, which doesn't surprise me- it could have been a dealer-installed extra.

So you found the ground, the brown wire. Make sure you ground your new CD player and anything else to the same point under the dash-- there's a male faston terminal as part of the body sheetmetal where everything attaches.

The blue wire. . . not noted on the factory diagram, although blue is often used as a remote amp turn-on lead. You didn't say whether the prior tape deck used a remote amp, that might be it.

The other two wires, a black and a white/red, well, if you are getting 12V out of them when the ignition is on, there's your solution, just hook those up to the SWITCHED 12v and ground wires on your CD player wiring harness.

The switched +12v behind the dash is a red wire with a sprial black stripe. You COULD hook up to that, but that's actually used to drive the gauges and could overheat when the head unit starts drawing power.

I agree with Vintage's suggestion-- run everything new down to the fuse box. That's actually very easily done: once you remove the carpet in the trunk and the cardboard panel that covers the heater, you will see a few circular rubber grommets up in the corner of the trunk on the port side. Coat your power wire with motor oil and shove it through next to the factory harness.

Good luck!

spyderman · 10-13-2003, 09:17 AM

I'm an AE not a EE, wires scare me. Never done rewireing before, I would hate to blow something up on the car just to have good tunes. I'm sure it's an easy thing, but need to swim in the shallow end before the deep end.

spyderman · 10-13-2003, 09:22 AM

Previous deck didn't have an amp, just four speakers and the deck. I hook the brown ground wire into the ground wire in the wiring harness that came with the CD unit right? Or is that the black wire? I knew I should have paid more attention in my EE class...

bell · bell's Garage

the brown will be ground.....
being it is a 70' there will only be a "switched" wire, you will need to run a constant wire to the battery for an aftermarket radio.
the third wire is probably illumination (works with parking lights).
ise a multimeter or test light to check these wires and simply solder and tape them good and your there.
you could also use automotive crimp caps (not the screw on home ones) and make sure you crimp them well.

MonkeyBoy · 10-14-2003, 09:57 AM

Doesn't the clock run off a constant 12V? I agree that the best thing to do is go straight to the source, but I would be surprised if there isn't ANY +12V constant in a 70

bell · bell's Garage

there will be constant.....just not at the radio, unless there was ever a newer radio in it which required constant for memory.