I suspect there maybe some wires touching in one of the doors.
I have recently just hooked the drivers door speakers back up (6.5" components)
and it would randomly have a fit (continuous bottoming out) so i had to pull the plug, would do it even if stereo was turned off but amp still on.
Would this be the speaker wires shorting out?
All 4 speakers did it, but havent done it since ive disconnected the drivers speakers again.
Will go through and check wiring in that door out again, but i did think it was odd that all 4 spaekrs were doin it (off the same amp) sub off a seperate amp wasnt doin it.
cheers for the help