HELP: Troubleshooting speaker problem, 2004 LC with integrated Nav (1 Viewer)

[hatchethead]

I few weeks (months?) ago, my front speakers went silent. I was not messing with anything in the dash or behind the doors or whatever.

Today, I decided to dig in to try to find and solve the problem. This is what I know:

(1) both front speakers (tweeter and mid-range) on R and L doors are quiet while mid-range on rear doors and (I think) subwoofer are working fine;
(2) multimeter continuity test on a rear door speaker passed but continuity test on both front door speakers (mid-range) failed;
(3) the quiet speakers are fine and functional;
(4) all the harnesses behind the radio and Nav unit are solid; disconnection tests suggest that the only disconnecting the main power harness effect audio.

I'm now suscpicious of the amp under the PS seat. How do I test that? Do I need to remove the PS seat to work with the amp?

Is there anything else I should be looking at?

Thanks in advance for whatever advice the hive mind can share with me before it starts to rain.

Jason

 

[hatchethead]

UPDATE: Little progress.

(5) Should have mentioned that I tested all the fuses. They all tested fine. But it's worth noting that the front speakers do not appear to be on their own fuse, according to the wiring diagram in the FSM.
(6) All harness connectors behind the radio and to the amp under the PS seat seem to be solid.
(7) Because the wiring diagram shows that only the front left speaker and tweeter pass through the navigation ECU from the amplifier (the front right speaker and tweeter and the rear speakers and both come directly from the amplifier), this suggests it's could a problem with the amp or the radio and not the navigation ECU.

I'm trying to figure out how to initiate the radio diagnostics. The FSM instructions are for the non-Nav radio. My Nav-integrated radio doesn't have the same buttons.

Any pointers/suggestions would be appreciated.

 

[hatchethead]

I brought my rig to my mechanic with a list of a few things that I was working on, and this speaker issue was among them.

He immediately went to the front PS kick panel to look at the wiring harness.

The Factory Device Manual (FSM) shows that the wiring related to the front speakers passed through harness connectors it identified as IV3, IY2, B8, and IC2. The IC2 harness is behind the front PS kick panel. My mechanic looked at it, saw that it was disconnected, connected it, and after turning on the radio shows that he just solved the problem.

LESSON: The FSM is a good guide to possible wiring problems. Search out the simple ones, first, like the harness connectors. And have a mechanic who has a good sense of humor. Shout–out to S&M Auto in Camarillo, CA.