~ Discovered crackling static from the speakers while the radio was OFF in the garage queen roadster yesterday.
~ It must have been an RF signal to make the static sound through the speakers.
~ I will find the radio fuse and disconnect it to see if it goes away. If if persists, I will suspect the batteries in the alarm module although I have not read of reports that static is one of the symptoms.
~ The 1K HZ tone thread in this section doesn't seem to address this issue as it is not a tone but static crackling.
~ Any ideas folks? Thanks.

 

Well, the amp is powered at all times, what I don't know, is how much is switched on when the head unit is turned on - but I do know that battery power is applied to the amp at all times.
If you pull the amp fuse (fuse 23 in some models), the amp is powered down.

If you still hear it, then it's induced voltage in the speaker leads (not very likely) and nothing to worry about.

If you no longer hear it, it's coming out of the amp - which leaves us the question: "Where is it coming from"? And I think suspecting the alarm module is a good place to start.

 

Not questioning your thought process above because I have a respect for your knowledge regarding electrical circuitry in the Crossfire, but the wiring diagram for the stereo system states that the Fuse 23 leg feeding the amplifier is HOT only during ON/RUN, and START. Looks to me that the Fuse 8 leg, which is a direct feed from the battery to the radio, does provide power back to the amplifier via terminal 4. And there looks like a hot connection between circuits Fuse #8 & Fuse #23 via terminal connections 4 & 9 on the amplifier. Several cross-feeds going on if I read the wiring diagram correctly. Is that the case/ Comments?

 

In what manual?
2004 service manual says "Hot at all times":



2005 Service Manual says "Batt(ery) Red" which is, again, hot at all times:


No, that feeds the AM/FM head:




This does not describe the wiring of the head and amplifier at all. I do not understand where you are getting this. Notice that "Pin 4" is meaningless, "Pin 4 of connector A on the Radio" would be how you'd describe the above feed to the AM/FM head - without the letter designation, it's hard to determine what pin you are talking about. But there is no feed of power from the AM/FM head to the amplifier. There IS an enable from the AM/FM head to the amplifier, as well as the actual power feed to the antenna preamp, as shown below.

 

2007 Manual says different. My error in not making clear what year wiring diagram I was referencing. Somewhere along the series, looks like circuitry was modified. Sorry for the confusion. The circuitry on my 2007 Coupe isn't even pertinent to this original thread. Like I said, just curious and wanting to learn more about the circuit. Thanks for your comments.

 

This is a BIG problem, they made little changes time and again. Remember my "Always hot cigarette lighter mod"? Well, in 04 Coupes and 05 Limited/SRTs it works as described, but 05 and later Base/SE models ya gotta use a different fuse because the wing motor fuse, in later years, is not wired to battery as it is in earlier years. Now with you telling me the above, I realize that they may have moved several items to the "switched" bus in later years.

This is why I caution people to be very careful with the wiring diagrams, you can't trust them 100% because of all the changes. It really is a pain....

 

~ I didn't pull that fuse..yet..mostly because that car stays in the garage and there was no urgency to track down the source. Today, however, I needed to move the car to prepare for the alarm replacement...wipers, cowling, and started the car and listened while it was warming up. The radio was off, after the 35 second warm up listening for the air injector pump to stop and the RPM's to drop, the low rumbling static began. I switched on the radio, the chrysler displayed, then the display read PROTECT or Protection, not sure which...I had never seen this display before, all the while the static was rumbling..I pushed "OFF" on the radio ****...then silence...no static. I tried again to reboot the radio and the static returned..tried to search for a station with no luck either. The radio antenna must have an issue. The only thing with the radio that I was aware of was the floppy deteriorated rubber support for the antenna of which I am searching for 2 of them.
~ Several Mercedes share our security alarm, The prices at Autohausaz, rockauto, fcpeuro, have ALL gone up on front end parts as well as our alarm. Does anyone have a source for the best value on replacing our alarm modules?