Another poster and I suggested sniffing around using a small AM
battery-operated transistor radio. The OP doesn't say if he has tried
that or not.

H. R.(Bob) Hofmann


an alternative is to build a "sniffer" antenna. this is a small loop antenna
wound at the end of non conductive rod. the coax connects to the car radio
(or a portable) you fish around the engine with this in relative safety
looking for the spot that makes the loudest similar noise.

for what it worth my 2000 cherokee exhibits similar issues. i get clicks and
pops when turn signals are in operation. sometimes when wipers are in
operation.
i find that the added interference make Rush Limbaugh slightly more
palatable.