Hi, I recently installed an entry level kenwood CD player into my Ford Ranger XLT 2001. It worked well until i added 4 new speakers, a four channel amp and a 12 inch subwoofer. Anytime i turn my truck on the cd player will either drop my speakers and continue to play the subwoofer, or go into protect mode. The door speakers are wired to the head unit at the moment because when i wired them to the amp i experienced speaker noise/alternator whir. The weird part is when I disconnect my rear right speaker it works flawlessly. I have tried running new speaker wire to said speaker, and it worked for a day; but the problem resurfaced this morning.
Anyone ever experience this? im thinking maybe some of my equipment is defective?

The 4 channel amp is either bad or not grounded correctly or there are other grounding problems in the system.

What make and model is your 4 channel amp, the sub, the sub amp, and the 4 new speakers ?

Please tell me you aren't powering 4 full range speakers and the sub with the 4 channel amp ?

It is possible to run 4 full range speakers and a sub from a 4ch amp, providing the 4 FR speakers are ran in parallel on 2 channels & the sub is running in mono on the other 2 channels bridged (provided the amp is capable of that feature)

I ran a 4ch amp with 4 mids/highs & a single sub for over 10 years without an issue, but the amp was capable of 2/3/4 channel operation down to a 2ohm load.

It also isn't a good idea to run a 4ch amp with only 2ch connected. That could cause the amp to go into protection mode.

Could be the wiring from the amp to speakers is incorrect, has a short or the amp is defective.

The speakers shouldn't cause a short by themselves but if the wire passing through the door grommets had some insulation damaged, it could easily cause the head unit/amp to short. Also if the connectors to the speakers aren't insulated properly they could come in contact with any metal inside the doors & cause a short.

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'96 XLT, 4.0L, 4x4 Auto, Super Cab, K&N Filter, Dual Exhaust, 200 amp Alternator, Clear Corners, Explorer Power Seats & Console, 4x Fog Switch Radio Bezel, LED modded '01 Tails, Dirt, PICS

It's the redneck way of running a 4 channel amp to 4 full range speakers and a sub. It works.