Has your question been asked before?

[holdenboy]

Theres only one wire in the stock loom worth using IMO. The accessories wire, you can find using a multimeter or test light and turning the key.

Constant power can be obtained via the clock (if fitted), if not check any wiring looms up there (once again with a multimeter or test light) for power regardless of key position. Make a new earthing spot to a solid piece of metal in the dash, and you'll need to run new speaker wiring or upgrade the speakers as they use a "common earth" system for wiring which wont work with an aftermarket head-unit.

[taylorsvr]

I pulled out my Kenwood Stereo to wire-in some new speakers, now my head unit is displaying "PROTECT" flashing continuously, i managed to get rid of it for a while untill i had to unplug the harness again to do extra wiring, now this message has appeared again and i cant get it to stop. also i obviously cant use my stereo untill this message has gone away if you didnt get that already... i have tries the reset button a number of times and also pulled out the fuse and replaced it.. still displaying "protect" its driving me nuts because i just put in a nice new set of speakers but now i cant use them!!

[sweefu]

Have you checked your earth mate? Are all the cables properly shielded?

[wamboin23]

sounds as if youve got a short in the speakers somewhere, cabling or speakers themselves. i'm guessing the stereo shuts itself down and displays protect, to protect it from been damaged.

[HCVP]

Some simple trouble shooting to help you identify the issue.

Firstly , begin by disconecting your speakers all together.
Turn the head unit back on, do you still get the "protect" message.
If it dosen't , then you know there is an issue with your speaker connection.
Otherwise, it is an issue with your power/earth wiring.

If it is your speaker wiring causing the issue, then connect each speaker one at a time, until you find the speaker responsible for the problem. Once you've found the speaker causing the issue, trace the wiring back to the speaker itself, checking for any loose ends, exposed wiring ect. Better yet, just re-wire that speaker if possible.

Be sure to have your battery disconnected each time you pull your head unit out. It dosent matter so much when connecting speakers so long as the head unit is switched off, but it's advisable that you do so, as a safety pre-caution.

If your speaker wires aren't the cause of the fault, check that your power wires are correctly crimped, soldered (which ever your method) and that your earth wire has a secure connection.

Also check that you haven't knocked a wire loose in the ISO plug (the plug at the back of the head unit ) especially if you've been removing, and re-fitting your head unit quite a bit.

[Tasmaniak]

look, failing this, Kenwood H/U have been known to throw themselves into protect from time to time... unplug and reconnect will remove it from this mode and it will run for another 12 months before going into protect mode again....now, donsidering the fact that you've removed it and installed new speakers....fair chance you have a short.