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Discussion Starter · #1 ·
I recently replaced the factory head unit in my 2008 xB and everything was working fine until a few days after the install. Now, at random times when I shut the xB off the head unit will revert to factory settings (demo mode). Ive replaced the 10amp fuse in the back of the head unit (sony) and checked all my connections in the wiring harness adapter (soldered together) and it's still doing it randomly. Sometimes after a work shift (about 8 hours) and other times lasting several days before it resets itself. I've read about the fuse under the hood that controls the dome light but that light has never had an issue. Any help or similar situations would be awesome, I love the new unit because of the built in BT but at this rate I'm getting tired of redoing all the settings every few days.

Thanks in advance for any help :)
 

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Try reversing the red and yellow strands within the ISO connectors, I had to do this when I put the Kenwood DAB radio DD head unit in my bB. I had thought that only VAG cars used the opposite colours for permanent (memory) and accessory (I/O & spur for the aerial amplifier) but then suffered exactly the same issue as yours and then realised.

So instead of red to red and yellow to yellow, connect red to yellow in both directions. The contacts in the nylon blocks can be pulled out easily on yellow and red positions on ISO harnesses for this very reason.
:)
 

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Discussion Starter · #3 ·
Thanks for the input! By ISO connector i'm assuming you're talking about the connectors in the factory harness?
 

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No, the Toyota loom uses Philips connectors which are smaller than the ISO standard ones. The ISO harness will be the one that connects a non manufacturer-specific head unit such as Sony, Opus, B & O, JVC-Kenwood, Pumpkin, Siemens and similar aftermarket brands to the original Philips-style terminal block in behind the dash. I've found images on the web to illustrate what I was referring to. This diagram shows the ISO plugs that connect to the head unit:



So pins 4 and 7 above are the ones that need to be crossed between each other's positions in cases where the stereo works, but doesn't save presets or user settings.

And this shows the typical harness to connect from an aftermarket radio's ISO standard blocks to a Toyota's loom, which still uses the smaller Philips connectors as they work and these adaptors are cheap, readily available from any car audio parts place and - the variation in the live and accessory colour & position apart - provide a universal standard that makes for easier fitting of non-factory ICE:

 

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Discussion Starter · #5 ·
Fantastic info, thanks so much! I tried switching the wires and it wouldn't hold memory at all, every time I cycled the ignition it would lost memory completely :( I had considered at one point that my battery was the culprit but it's never had an issue starting and even last night I left the dome lights on by mistake and it didn't even hesitate to start this morning. It's so hard to troubleshoot an intermittent problem like this
 

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Lots o leather and copper
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You have one of three issues.

1. The yellow constant power wire has a loose connection and is loosing power from vibration every so often.

2. The black ground wire has a loose connection and is loosing ground from vibration every so often.

3. The radio is defective and has a loose connection on where the connector on the back of it is soldered to the circuit board.

I vote for option 1 or 2.

What type of connections did you use to connect the Sony radio to the stock harness? Check the connections over with a multimeter while wiggling the wires around to see if either the yellow or black loose continuity while doing it.
 

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Yellow is acc+, red is constant. VAG were the only manufacturer to use Sony as o/e, hence my suggesting the usual swap between red and yellow, but if the yellow were already the constant supply, then the presets would remain stored since the acc+ wire would lose the presets once the storage had discharged whereas a loose or incorrectly connected constant feed would cause the set to go down randomly but the presets would still have been written to system settings, so then, each time the set powered itself up after such an event as a shaky connection, the settings would be intact.

---------- Post added 02-15-2018 at 12:09 AM ----------

Edited Thursday, 00:04hrs: Also, a loose earth wouldn't cause the settings to be lost as there are three separate paths to earth, only the one of which would be needed to maintain settings storage regardless of which others were loose, so only if the aerial braid - and/or the light green which is always earthed unless having the set's display lit up while driving is illegal in your location - were also loose would that cause presets to be lost.
 

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Lots o leather and copper
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On aftermarket wiring harnesses yellow is constant power and red is ACC. This is a definite as I was a car stereo installer for 15 years, the color codes are ingrained in my head. lol

Just realized that I mis-read the OP's post and combined the symptoms of his first post and the one after switching the yellow and red.

If I'm re-reading this correctly it's just going into demo mode on it's own but not losing memory? If so this is almost got to be something internal to the radio. I would recommend going through the radio manual and seeing if there is a setting to disable demo mode. I remember Sony radios being a pain to take out of demo mode sometimes but I can't remember where in teh menus it is to turn it off.
 

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On aftermarket wiring harnesses yellow is constant power and red is ACC...
The red and yellow are as stated in the drawing at pins 4 and 7, swapping is usually only required for VAG brand cars and a few random things from the other two large German manufacturers. I've only been in the trade for thirty odd years myself, but in an average week when I was doing the fitting for a dealer group, the single most common cause of settings being lost when the set was powered down was that the car's own loom had red for constant live and the set had yellow, hence the way these leads are made to be swapped for cars where yellow was the constant supply from the battery.

I know of many fitters and engineers who didn't realise this because they had only worked on cars whose connectors' insulation colour matched from the o/e loom, right the way through the ISO link to the back of the unit.

While looking for another link to confirm that which I already knew to be the case, I found that some - but not all Datsuns also have their red and yellow crossed over between the loom and the set, this was definitely not the case when ISO first replaced DIN so it looks as though standardisation is still not something that all SMMT members can rely upon!

The following thread, from the UK Golf forum, explains and illustrates in a way that shouldn't confuse the o/p any further:

GolfGTIforum.co.uk - An independent forum for Volkswagen Golf GTI enthusiasts.
 

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Lots o leather and copper
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The red and yellow are as stated in the drawing at pins 4 and 7, swapping is usually only required for VAG brand cars and a few random things from the other two large German manufacturers. I've only been in the trade for thirty odd years myself, but in an average week when I was doing the fitting for a dealer group, the single most common cause of settings being lost when the set was powered down was that the car's own loom had red for constant live and the set had yellow, hence the way these leads are made to be swapped for cars where yellow was the constant supply from the battery.
Oh god, I'd forgotten about that with the VW harnesses. lol I remember hating that when it happened the first few times. It's been a few years for me too, not quite as long it's on been 15 years.
 
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