Troubleshoot 2 Pioneer Installs

Ok, for all you late night forum readers. I need your opinion on a couple of installs I tried today. I am a little confused, and would like your opinions to finish them up tomorrow morning. Vehicle 1 - 2001 Chevy Impala Vehicle 2 - 1992 Mistu Mirage Deck 1 - 2004 Pioneer DEH-MP4600 Deck 2 - 2003 Pioneer DEH-3500 So I hooked the wiring harnesses (Metra) up to both units. Started with GND, then Constant, then ACC. For testing purposes, I only connected these 3 wires up to the factory wiring. Turn the key in the ignition, on vehicle 1, and no power to the deck. Started the vehicle, and still nothing. Factory deck works fine, though. So I pulled out my DMM and checked the connections. Gnd was good, Constant read 12.4V, that was good. Accessory was 0.01V with the key out of the ignition. Turned the car to ACC and the reading went only up to 0.2V. A little troubling. So in a pinch, I connected the Constant and ACC lines together. Bingo, the deck turns on and works as I always had hoped and dreamed. The funny thing is that the second deck (same manufacturer, but different years) does the same thing in a totally different vehicle. The only way I can get either to turn on is to wire the 2 power lines together. The Mirage's first aftermarket deck works fine, too. That is not the right way, obviously, but atleast I know I can get them working. What do you think I should do? I can grab an ACC line from the cig lighter in the 2001 Chevy, but I don't think I can do that in the Mirage. Is this a good idea? What are your opinions? I am anxious to get these installs done, and looked foolish when they did not go smoothly. I have trusted Pioneer for the last 8 or so years, but this is just a little to wierd. Thanks! DXAV

It doesnt really matter where you grab the ignition from as long as its a good solid source. I generally just runa  fused line right from the steering column but to each his own.double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

in the 01 impala you have to run your own ignition wire with any aftermarket radio install...fact ign. wire at the radio doesn't put out the full 12v...problem 1 solved right there...as for the 92 mirage you might want to go ahead and check your fuses unless you are sure about what you tested in which case that is just a coincidence that there is a problem with the ign wire...but as for the impalas...all of them are like that...its to be expected...

Just one more suggestion.......when I need a switched 12v source , I take one from a spare slot in the fuse block with a spade terminal If I can , if not , the cig. lighter works as well.99 F-one fitty

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sorry...i forgot to say that my advice with the fuses on the mitsu is only valid if the fact radio isn't keeping radio stations...some of those have two fuses for the radio...one for constant and one for ign...if constant fuse is bad it still may work other than the memory part...sounds impossible but i have run into this a couple of times before...contrary to popular belief when a fuse cracks(blows)...it doesn't always break big...in my shop we call it a hairline fracture fuse...the tiny crack still allows it to put out some voltage...but not enough for the aftermarket radio...its a shot in the dark but just checking...i know how frustrating it can be going to bed with the notion that the car beat you...

You people are fast! Thanks for the help. Here are the issues I have now: 1. The Impala has a beefier wiring harness. The front speakers are wired to relays with the ACC line on each of the pins. Then the harness connects to the factory connector, to the Pioneer harness, AND back to the orininal HU. I have to install the factory HU into the trunk to maintain the security and door chime features of the car. The Taurus is like that too, but I have no problems with those. 2. bumpingjeep, what do you mean they are all like that? I have installed tons of HUs in newer cars, Chevy included, and have never seen this before. 3. So grabbing ignition from where would be the best? 4. With the Mitsu, there is only one fuse for the radio. The older HU (aftermarket) works fine, just not the new Pioneer. I did get beat today, all 3 installs went poorly, and I only worked for 4 hours today. Thanks for all your help, please keep the suggestions flowing! DXAV

check your voltage on the mitsu...some of the older radios have and in line voltage regulator on them dropping it down to 9 volts...again a shot in the dark...but just checking anything...and are you sure that there isn't a fuse under the hood...and have you check the older hu since tried switching the decks...that is...have you hooked it back up to the fact wiring and confirmed it STILL works fine...if not...do not rule out any possibilities...as for the impala...yep...all the new ones are like that...just not all cars...specific chevy models are like that...grabbing ignition wire from the ignition column would be best but if all you are putting in this car is a radio the fuse box will do fine also...just go to the windshield wiper fuse(25amp)...if you are putting any amps in i do not reccomend this though as the fuse box is one of the easiest places to pick up noise...good luck

Yeah, I measured solid 12.4VDC on both vehicles. I am doing just the upgraded HU, nothing else, so I will make it easy on myself. I checked the handbook for the mirage, and there is only 1 radio fuse. I don't have the factory HU in the Mirage, but I do have the old deck that was previously installed. This works perfect. But it is a much older cassette, that may work under 10VDC, which may be why I can get that working fine. I will try the cig lighter first, and then the Ignition wire, then the Windshield wiper last. Thanks for the help! DXAV