Need help:98 S-10 Blazer/Pioneer DEH-P47 install

[RolloT]

Bought this to replace the factory Delco junk and since its a 1.5 DIN it seemed pretty straightforward. I popped the dash and removed Delco, spliced the Pioneer connector to the Scosche No-Cut connector and plugged the existing connector (that was plugged into the Delco) into the Scosche. Plugged the other end into the Pioneer, turned the key and..........nothing. No power at all to the unit. I replaced the inline 10A fuse and the 10A in the fusebox without any effect. I even tried disconnecting the Pioneer and reconnecting the Delco which proved that I screwed something up because now the Delco is dead(no power to the unit). I need some bigtime help because now the wife is standing over me reminding me every 15 minutes of my famous last words that "this was going to be easy, don't worry". What did I do wrong and how can I fix it?

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[Colt9699 10+ year member]

in a gm vehicle the antenna must be connected for it to power up.

Just a thought.

 

[KaeZoo 10+ year member]

in a gm vehicle the antenna must be connected for it to power up.
Just a thought.

That's not true of any vehicle radio that I know of, and it's definitely not true of GMs. If you have a head unit that won't power up unless you plug in the antenna, it means you don't have a proper ground.

For the original poster, the most likely cause is still a blown fuse. There are always (at least) two fuses in the vehicle that supply power to the radio: a constant power circuit and an accessory power circuit. Very often one of the fuses isn't labeled as a radio fuse. You need to check all vehicle fuses, including the under-hood fuse box.

 

[Colt9699 10+ year member]

I had a Pioneer deh p4400 in a 1991 chevy blazer and it would not power on unless the antenna was connected, just my experience.

HU was grounded well too.

 

[KaeZoo 10+ year member]

I had a Pioneer deh p4400 in a 1991 chevy blazer and it would not power on unless the antenna was connected, just my experience.
HU was grounded well too.

If you think about it for a bit you'll realize that there's no way the lack of an antenna connection could prevent your head unit from turning on.

You can connect your head unit to the battery, with the black wire connected to ground and the red and yellow connected to the positive terminal, and the head unit will turn on. You can do the same thing on a test bench, and it will turn on. You can wire your head unit to a computer power supply in your bedroom, and it will turn on. So if you have power and ground connected properly in the dash of a Blazer, why would you need to plug in the antenna before it would turn on?

I'm not trying to say what you're describing didn't happen. Most likely you didn't have as good a ground as you thought you had; maybe the ground wire came loose from the head unit plug, or maybe you had a defective adapter harness. If there's voltage on the red and yellow wires and ground on the black wire, any after-market head unit will turn on with or without the antenna connection.

 

[RolloT]

I forgot to mention, my dash lights went out since the install so I will try to locate that fuse as well. How can you tell when these atc/atm type fuses are blown?

Thanks for the responses.

 

[KaeZoo 10+ year member]

The best way to test is with a multimeter or test light. If you look closely at a fuse while it's in its slot, you can see two test points at the top of the fuse where you can touch the metal. Set the multimeter for DC volts and attach the black probe to ground. With the key on, touch each point at the top of each fuse with the red probe. What you're looking for is a fuse that shows voltage on one point and no voltage on the other.

If you don't have access to a multimeter or test light, then you'll have to remove each fuse and examine the filament inside it for a break.

 

[lilmaniac2 5,000+ posts]

even examining the filament inside to test it isnt 100 percent... if you dont have a dmm easiest way to see if one is blown is to replace it. You can buy a bulk pack of fuses for like 5 bucks and just replace anything that says "dash" on it in the fuse panel

if your dash lights went out during your install you must not have unhooked your ground to your battery... shame shame //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[RolloT]

Turned out to be another fuse (15A) that was bad. Thanks to all for your help.