OK, an electrical mystery for the electrical experts out there. The car is an 83 CDV. I put in a Pioneer DEH2700 head unit. Bought the harness and all the right stuff. After installing, I have a parasitic drain. Now, the harness I bout had a separate little harness for the constant power line which didn't match the plug in the car (the main harness matched fine). So I had to cut the constant plug and wire it direct. I tested both of those wires and the brown one tested as ground. There was a black wire in the main harness that also tested as ground.

So I hooked both the brown wire and the black together to the black ground wire on the stereo. Everything worked but had the drain. So I went back in and cut out the brown wire (had to try something). Everything worked but still had the drain. So tonight I cut the ground wire and put an ammeter in to measure the draw. The stereo was running but showed no amperage draw. Disconnected the meter (possibly to scratch my head http://cadillacforums.com/forums/images/smilies/hmmm.gif) and the stereo was still running. So ground wire not connected and stereo still working. Isn't that impossible?

So I think about it a few moments, and I wonder if it's ground through the antenna lead (power antenna and all). So with stereo power off but key on, I pull the antenna connector out. There seems to still be power to the stereo but the lights all flash. I try to turn the stereo on and the antenna attempts to raise but then doesn't and I lose power to the stereo altogether. Plug the antenna back in and everything works again. So that's how I left it, the black ground wire on the stereo disconnected, the antenna plugged in. The stereo is working, but it will be a couple days before I know if the drain is cured.

Yep, the drain is so low it takes about 3 days to get down far enough for the car to not start. So what do I have happening here? I am sure it has something to do with the stereo, but can someone explain all this to me?

Do you have a switch on your dash for raising and lowering the antenna ? If so you may have tapped into the antenna relay and without a GOOD ground (ground from the antenna isn't good) you could have a drain.

If I remeber correctly the 3 plugs for the radio are white, blue and black and the black (or whichever was the one closest to the top of the radio) is the one for power.

If I am right we can work from there

Thanks for your help, you must have a good memory. You are right, the plugs are white, blue, and black. The black is the power. Coming into the black (the original plug) are a yellow with black stripe, a red, a black, and a gray. The yellow/black is hooked up to the red (key on power) wire of the stereo. The red is hooked up to the blue (antenna remote) wire on the stereo. The black was hooked up to the stereo ground. The gray is not hooked up and my schematic shows it is the dash light dimmer. Really, not much to it.

The constant power is an orange wire in the dash hooked up to the yellow constant power on the stereo. There's a brown wire with the constant power that tests as ground but is not currently hooked up.

Taking a que from your post, I have now run a ground from the stereo to a factory ground point on the steering column bracket. I'll have to let it sit for a day or two to see if the battery still drains but maybe the ground wasn't good before?

I'm open to any other ideas you may have.

I almost forgot, no switch on the dash to raise and lower the antenna, it just goes up and down when the radio is turned on.
Thanks.

Well, still have the drain even with the new ground connection. I'm starting to think it's something other than the stereo, unless the stereo itself is bad. I've checked the trunk light, as someone suggested that, but it's fine.

The other problem I have with this car right now is that when the climate control is switched to off, it blows hot through the defroster. In fact, only when it's switched to "auto" and set to the lowest temperature does the AC blow cold.

Could the climate control problem be related to the drain? If so, how do I begin checking it?

That is most likely a vacuum leak in the a/c controls, the default position of the climate control when all vacuum is lost is defrost and hot so you can see out of the windshield when all goes to hell ;)

Thanks for the info. I'll check for vacuum leaks before I start replacing any expensive stuff. Now about the parasitic drain, does it sound like the stereo connections are fine? What kind of drain should I normally see on the battery when all is well? I am in the process of bidding on a new multimeter on eBay so I can start measuring current drain, but I'll need to know what is normal. . .
Thanks again.