Sounds like you have a loose connection somewhere. Does your car have the optional subwoofer under the seat? If so there have been problems with others on the forum having a hum/buzzing sound from the subwoofer that resonated through the cars interior. The sub has battery power running to it through 2 wires and that powers it's own amp. Now there is 2 more wires that run to it's input side from the radio. If one of those 2 wires get a loose connection then the sub will buzz and crack intermitently like when you hit a bump or something jars that connection. I would locate the wires and wiggle them to verify this and if so, fix the loose connection. Hope this helps. DCO
Thanks for the very helpfull information. I did wiggle the wiring where it enters the sub w. I was unable to produce the hum or pop. I was able to unplug the sub and this wnded the problem. I apprciate you assistance. I would also welcome any further suggestions on how to locate the problem wire/short. Thanks again.
Hi Cubby. Unfortunatley I don't have a wirring diagram for the sub. I've looked over the internet and searched it on the forum and some links point to an Evilution site diagram that I haven't been able to access. I guess alot of the "radio" links here are old. Also it matters what year Fortwo you have and what radio option you have, radio 9 or 10, entryline, highline etc,... I have an aftermarket subs and satelite speakers in my Fortwo and decided to keep the entryline radio I have and used a line level converter from the radio to connect it to the amps. But at any rate there should be 4 or 5 wires going to the sub:
One will be 12 volt power to the sub.
One will be 12 volt ground to the sub.
These will both be just standard wires
One will be input audio to the sub from the radio (positive wire)
One will be input audio to the sub from the radio (negative wire)
Now these 2 wires may be combined into a single coax cable with the center wire being + and the - wire being the braided shield.
It may or may not have a "trigger wire" which runs from the radio to the sub and tells it to turn on the sub when the radio is on.
I know this is a generic explanation, but it's the best I can do since I don't have the factory premium sound system. Maybe someone else can provide the proper wiring diagram for us for the American Fortwo. But we will need to know the year of your Fortwo because they used Grundig radios and Mobis on later years. DCO