Radio install, please help getting power.

[mjjstang]

ok I just bought an alpine unit, and got the harness to go to our plugs, 91 well when I bought the car, there was no radio, and there were a few misc connectors, like maybe this guy had trouble with his and was trying tobuy stuff to fix it, and then just gave up, well i have 4 plugs, the big one, the smaller one, (those 2 are the only ones that go to the new harness) then ther is a smeller one even, which only has 4 pins, only which 2 or 3 have contacts in them, then I have a smaller black one that has one wire coming out, , then obviously my antenna, well Im using the antenna, and the larger one, then the slight smlaler one, (i can take pics if I must) well so last night I decided to install it, no luck, then today I realized that the ground on the harness I bought, doesnt have anything to connect to where it meets the harness in the car, so i realized I must make a ground, this will solve my problem, Ok it did solve the power to the head unit issue, as I checked the main battery line, getting 12 volts, and ignition getting a little less than 1 volt, so im getting power, BUT the radio does not work, there is no display, just power feedint to the plug, as far as the radio, NOTHING, please someone help. im going to go back there and exchange the unit, but ive installed these before, and had no trouble like i am now. thanks for any help.

[projectRDM]

1 volt is not enough to trigger the radio. You should have an orange/green for constant and a blue for ignition, both reading 12 volts. Nothing else matters to make it work.

[mjjstang]

r240, thanks very much, but also I realized I need the antenna plugged in too or else it doesnt work, maybe you assumed I had it plugged in already, gotta love having to buy a stupid antenna adapter, but yah I tested my buddys car and got a 12 volt, so then I decided to splice into my water temp gauge for ignition and bam. it worked, also, is maybe the antenna a ground, because I noticed on my buddys car that he wasnt using that ground either, and I had already pulled my makeshift ground, maybe ill put it back on, and see if it works without the antenna, not like it matters, just wondering if the antenna is the ground source for the radio, but id never run the radio wout an antenna anyway,

[projectRDM]

The radio is grounded through the chassis. The antenna will work also, but that's not the common point for a ground.

[mjjstang]

oh yah that makes sence seing I did not have the radio in the dash when I tried it, all is well though. thanks.