I've installed an aftermarket JVC headunit with the appropriate harness. The headunit was somewhat difficult to install because of all the extra cables it has. Now, I think while installing the headunit, I damaged the wiring harness since I now do not have sound coming from the front left speakers. I tried the original deck to make sure I didn't damage the OEM harness/wires. I do get sound out of all speakers with the OEM deck, so speakers are fine and OEM harness/wires are fine. I also tried another deck (same model) with the same aftermarket harness and still no sound. So I don't think the deck is the problem.

Now, my question is how to test if the aftermarket harness (specifically the wires for the front left speakers) are damaged/not making contact. I've purchased this:

http://www.canadiantire.ca/AST/browse/3/HouseHome/2/Electrical/ElectricalTesters/PRDOVR~0520059P/Mastercraft%2BMini%2BAnalogue%2BMultimeter.jsp

(a multimeter) in hopes that I can detect if there is a signal in the suspected damaged wire. I really have very little knowledge with car audio and any help in diagnosing this problem and fixing it would be greatly appreciated.

 

take the multimeter set it to ohms the Greek "u" thing. Place one test point on the speaker's positive connection, trace that wire back to the head and place the other lead on the positive left speak connection on the head side of the harness. Assuming there is a connection you should have a very load reading of only a couple ohms. Check the ground as well if it is also part of the harness and not just grounded to the chassis.