justind89

Ok, so i'm trying to run wiring for my new head unit, but with a continuity checker (just one of those screwdriver lightbulb type things) it definetely works as when i touch the positive terminal it lights up, but when i try to check it against every single pin on the radio plugs none of them will light up with the ignition on or off. i don't see how this is possible as i'm sure the stock radio needs power since even lexus doesn't have radios that run off dreams and magic

mick_foley

The only thing I can tell you is what you seem to already know - you must be doing something wrong with your testing. There's got to be constant power in there somewhere as it helps the radio remember.

This might be an odd thing to ask but sometimes simplicity is our greatest foe. Are you checking the plug coming from the stock wiring or the radio? It's obvious that the plug from the radio has no power at all without being connected to the stock wiring.

justind89

yeah, new radio is sitting on the table a few meters away still, i checked all of them. i have heard that it doesnt have constant power, whihc is possible, i mean you dont need power on all the time to remember 6 stations (which is all the stock one did) it's just strange. but the main problem is ignition, i'll be running a new cable for the main power to the new head unit but i need a way for it to let it know the cars turned on

mick_foley

I say the constant power is for remembering the stations because usually when the battery is disconnected (at least on most of the cars I know), the preset radio stations cease to exist. But even if there was no constant power, there would definitely be an ignition switched source of power going into the radio.

Maybe someone else can chime in with a better solution than "you are testing for power incorrectly".

I see you haven't been around here long. If no one has told you already, welcome to CL.

justind89

yes, i did just remember the battery, when i changed the battery i had to reset all my stations. well, just tried it again with a wire instead of the screwdriver tip in case it wasnt touching terminals properly, it lit up when touched on positive on the battery, but not on any of the pins. i used the same screwdriver to do this on my last car btw. also, thanks for the welcome! i plan to post a big diy post including all the little issues with installing a new system when im done (been taking some pics!) but jsut need to get through it first

JSM1284

Is the other end of the test light connected to ground?

justind89

yes. to make sure i ran a wire directly to the negative battery terminal. and it lit up when touching the positive terminal

JSM1284

Are you testing the connections with the key on?

esucaris1

Fuses???????????

justind89

tested it with key on and off. where are the fuses for the radio located? strange thing is that the stock radio was working when i took it out, so i dunno about that. ill check though

justind89

ok, so i've found switched and unswitched power on the amplifier harnesses (problem is they are under the passenger seat) i suppose i can run the wires back up to the head unit from . but its still perplexing that there are no power lines in to the stock radio. i'm jsut going to cut the plug off and figure it out. hopefully the wire i was using was jsut not quite long enough to get in to the oem plug