Kicker CXA300. 4 pulsating protection issue.

Your Bad PWM card
0.) 0 Vdc LN
1.) 12.89vdc LP
2.) 13.12vdc C
3.) .001 DC Pro
4.). 001 PWR GND
5.) .001 B
6.) 6.212 +12V/Bat
7.) 13.23 K
8.) 12.78 AA
9.) 5.541 Sig GND
10.). 001 E
11.) . 153-.000 F
12.) 3.534 D

I added a O pin because the PWM card has 13 pins and it was easier than retyping the whole thing.I also added test point nomenclature to compare against my notes.

The 0) pin should read 0Vdc. Is that what you see on this amp?

Notes from a known good PWM card
0) 0Vdc LN
1) 2.1 Vdc LP
2) .7 Vdc C
3) OVdc DCPro
4) 0Vdc Pwr GND
5) 8.4Vdc B
6) 14.2Vdc +12Vdc/Batt
7) 14.2Vdc K
8) 21Vdc AA
9) 0Vdc Sig Gnd
10) 5.7Vdc E
11) 5.7Vdc F
12) 3.5Vdc D

Some of this may not make sense, but compare one against the other. Tonight I will compare the two against my schematics. It's obvious you have no drive and appears to have an issue in the turn on or protection/mute circuit.

Also, Is there any chance you have PWM card from another CXA3004?
 
Recheck the voltages. Be sure you measure all 13 pins keeping the same sequence.

If you have 5.4 volts on Pin 9(signal GND), you may have an open trace or RP87 is open.

Pin 2(C) should .7Vdc. If it is 13.Vdc ZD1-5.1V zener may be cracked or open.