HU Intermittent operation - Bad internal relay?

[mgray]

Hey all, my first post here, hoping I can find some answers from you knowledgeable folk!

So my Pioneer DEH-P86DHR head unit is giving me intermittent operation. If the car isn't turned on for a while, the unit usually turns on with first start and will stay on until car in turned off. Then on subsequent times car is turned on, unit fails to power up. Its interesting that if it turns on, it will stay on until car is turned off. And if it fails to turn on, it will never just "randomly" turn on while driving. In other words, either it turns on and works properly the whole time from the start, or it doesn't turn on at all.

Checked all grounds for good connection and continuity, as well as the constant 12v(yellow wire) and the accessory 12v(red wire). I even switched the resistor and tired bypassing it with no change.

I'm thinking the internal relay is what's wrong? I took apart the unit as much as I can and couldn't find any burned out sections of the circuit board. I can't get the main board out, so I can only see the top of it, not the bottom. I'm not sure where on the board the relay is, or if it even has one.

Any ideas? Thanks

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[hatedonmostly 5,000+ posts]

Sounds like it's time for a new HU //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[keep_hope_alive Premium Member]

each head unit is different, and that one is old enough that failures are possible/probable. your diagnosis may be correct, but good luck finding it without a service manual.

you can look for service manuals online, but you usually have to pay like $10-20 for one.

PIODEHP85DHR-SM

I found it available at Pioneer DEH-P High Quality Service Manuals User Owner Instruction Manuals Schematics Brochures Literature Printed PDF (some FREE)

or

Pioneer DEH P86DHR Service Manual & Repair Guide - Download Technical

or

Pioneer - DEH-P86DHR/UC Service Manual on Windows Drivers Downloads