I have read many topics about the dreaded wiring to the rear trunk latch. My remote access never worked and now my switch
in the center console won't operate the latch either. I would be grateful for any help in accessing the wiring loom. Do I
need to remove seats and work my way back, or access via the trunk and work my way forward? Thanks in anticipation.

 

When troubleshooting electrical/electronic problem, always start at the output & work backwards. Start at the latch itself, is it getting power when the button is pushed?

 

Hi, I have checked the wiring at the connecting plug to the latch and have 9 volts at one wire but no changes when I key the remote. I understand I must press the detent button, once on the remote to unlock the doors and again within 30 seconds to open the trunk. I have also checked the wiring around the trunk hinge and stripped back the insulation but cannot see any damage. So....back to my original question, do I go in from the trunk or remove the seats and go in from the front?

Regards

Chris

 

In a US car, the gray connector to the trunk (boot) latch has three wires -
car's harness side:
black/yellow: +12v when either the console button is pushed or the keyless signal is snet
blue/black: +12v from the gauge assembly and/or trunk light when key is on
black: ground (earth)

these match to blue/light green, brown, and black respectively on the latch side.

When +12v is applied to the latch through the black/yellow, the solenoid is energized, and the latch opens.
when the latch is open, the blue/black is grounded, completing the circuit to turn on the trunk light
and dashboard indicator.

Some tests:
is the fuse good? in a US car it's fuse #26 in the under-dash fuse box
When you press the console trunk release, do you get +12v on the black/yellow wire?
is the black wire grounded?


Modifry's site will show you how to access the trunk release switch wiring if need be.

 

Hi, thanks for the information on the wiring. The site you refer to is about re routing power to the trunk
switch in the center console so that it can only be operated when the ignition is on. Definitely a good idea
for security. However, my problem lies (I believe) with a broken wire in the loom to the trunk latch. They
say it is under the rear deck where I can expect to find the problem. Guess I'll just pitch in and have a go.

Cheers

Chris

 

Having now stripped back the protective covers of my wires I cannot see any breaks thus far. I have determined that
the fuse is good. Trunk button works and opens the trunk but still nothing from the remote fob. Oddly I have voltage
in the blue and silver wire @ 10.7volts, 12 volts in the black and yellow wire when trunk button is pressed in console
but still no response to anything when remote fob is pressed for the second time. 5 seconds or not.

 

From what I have seen, if that part is not bad, the break is typically where the wiring loom bends from the trunk hinge into the car. I'd open the loom there and start testing for breaks. Also, you may not see a break as the insulation will look good, but the wire inside is snapped.

Have you tried a fresh battery on the remote fob? Another fob? Why are you so sure that the problem is in the car and not with the fob?

 

It's hard to tell from the diagrams, but I believe the output from the keyless unit joins up
with the output from the trunk release switch just to the rear of the left door, so only one
wire heads into the trunk. I believe that if either the keyless or the rear console button
works, it's not a problem with the wiring loom heading into the trunk.

 

What model year do you have?

If it's pre 2004, then the boot opening via remote doesn't work very well at all.

Try pressing unlock once, then pressing and holding - that sometimes works, but it never, ever works twice without actually starting the car in between tries.

 

I don't know if there's a difference between US and UK cars, but I've never had any
problem with the key fob trunk release on my 2001 - just today I opened it from
roughly 40 feet (12 meters) with no difficulty. As with the other keyless entries
I've used, it generally requires line-of-sight, and you need to hold the button
down for roughly one full second, presumably to reduce the risk of opening it
by accident. In my case there is no need to unlock the doors first, though IIRC
the keyless is disabled with the ignition on.