Dough1397

My trunk compartment light stopped working. I figured it was simply a bulb and thus got a replacement, installed it and it still didn't work.

I measured the terminals for the bulb and don't see 12V.

The service manual suggests probing the wiring harness for continuity from the harness to the connector in the trunk. How is this done normally? the further I can put the two leads on my multimeter is ~1.5m. Do techs usually just have long pieces of wire hanging around??

n2myg37

I've always used a tester that comes to a small point on the end of each wire for testing. Kind of hard to explain, but the tips looked like pencil. I would always insert the testers on the back end of the harness to get a reading.

rmfnla

Did you check for corrosion on the socket terminals?

That's the most common cause for this kind of failure...

DocJohn

iTrader: (3)

Corrosion on the (or a defective) trunk light switch is right up there with corrosion on the socket terminals. Check for both of these before you start looking for a break in the wiring harness.

rmfnla

Right; good call!

Dough1397

The socket terminals appeared to be fine, no obvious corrosion.

I don't quite understand where the trunk light switch is. Is it part of the trunk latch? On the trunk lid itself?

rmfnla

I need to look at mine to be sure, but it should be somewhere around the rim of the trunk opening so the lid activates it when closed...

Dough1397

I did some digging again in the FSM and it seems as if the trunk room lamp switch is part of the latch that is on the trunk lid.

Another big clue to the puzzle. I no longer get notifications on the display in the cluster that my trunk is open! I am positive I did in the past...

Can anyone confirm that the display indicates that the trunk is open with the ignition set to on and the trunk lid open?

rmfnla

Yeah, you will get a notification if the ignition is on and the trunk is not completely closed.

Perhaps the switch is malfunctioning, or maybe a software glitch..?

Dough1397

I am going to pop off the interior trim on the trunk lid and check the connector and harness. It is possible one of my many attempts to stuff the trunk full of stuff may have yanked a wire or connector (easiest case )

rmfnla

Trouble shooting 101: Always start with the easiest case...

Dough1397

Well it finally warmed up and I went out to check my trunk lid wiring harness. After popping off the trunk lid interior trim the wiring harness looked fine and was seated perfectly fine. I checked the rubber grommet to make sure the wires hadn't been nicked, everything looked good. So I put it back together. Was kinda hoping it would a simple lose connection . Where should I look next?

Instructions to remove trunk lid interior trim, note the rubber bumpers are annoying:
1. Remove handle to the right of the latch; there are four clips, two along each long side, start with the ones closer to the front of the car and you should be able to rotate it out thus avoiding having to pry out the other two clips.
2. Reach in handle opening, find the square back end of the rubber bumper. There are two tabs on opposite sides of the square. Press on one of the two tabs that hold rubber bumper in place to remove the passenger side rubber bumper. Once you get it past one tab you can wiggle it out easily and with no damage to the other tab.
3. Pop out the emergency trunk release (easy to wiggle/twist out).
4. Remove the many small round plastic clips with a small flat pry tool (super easy, look these clips)
5. Reach under the trunk lid liner near the rear bumper and get your hand into the trunk lid to release either one of the tabs on the driver side rubber bumper.

rmfnla

Just because wires look good doesn't mean they are good.

When you are checking parts and circuits you might want to use a continuity tester to make sure there are no unseen shorts or breaks...

[Edit: Oh, I see from your original post that you do use a multimeter, so I assume you are checking...]

Dough1397

I didn't actually check continuity in the trunk lid. I had lent my multimeter to a friend and didn't have it at the time.

Guess I'll have to wait for another warm day.

Dough1397

My trunk stopped opening. After taking apart the interior of the trunk and the passenger side kick panel, I found that there opens (i.e., lack of continuity) in the trunk wiring harness. The harness runs from the inside of the trunk (drivers side, beside the rear deck speaker), through the rubber tube near the hinges and into the trunk lid.

The blue and green wires are open, these wires connect the trunk latch actuator and the trunk switch to the BCM.

A new harness is just over a $100. My plan is to simply repair the existing harness. I'll try to remember to snap pics and post them here. As far as I know I am the only lucky owner who has had to deal with this =P.