Which is neg and positive speaker

Just got a new truck with aftermarket speakers installed.

I have the speaker wires hangin in the trunk problem is the wires have nothing on them to distunguish pos/neg.

I am being lazy and dont want to take of door panels to trace the wires is there another way i finding out.  If you tell me use an MM what seting also would help.

Thanks

Okay ford exp, no its after market wires ran to the back where Amp used to be. So i guess i am gonna have to take the door panel off then cause I cannot see the speaker cone.  Can I do It with just a DMM and if so what setting and reading am I looking for .

Thankyou

As far as I know the only way you can use a DMM to test for polarity is when you're coming from the amplifier.  Then you just hook up positive lead to positive wire, negative lead to negative wire, and if you're correct it'll show positive voltage.  If it shows negative, you gotta switch em around.

The speakers will read the same impedence regardless of what the polarity is, so that wouldn't work either.  Really the only thing you can do is hook up an amp to the wire and listen to it to see which sounds better.