Friday, April 27, 2007

Jaguar Journal Entry #2 - Trouble in the Trunk

This project is meant to educate
Click on any picture to enlarge, then F11.
This is a small trouble diagnosis and problem solving project.
After a couple of week's ownership I noticed the trunk release button worked only intermittently. Every other trunk control feature worked fine - key remotes, key, emergency release, and trunk release button on the dash. So this indicated there was an intermittent failure somewhere in the circuit between the lid button and the latch mechanism.
I began by removing all of the panels in the trunk to access the circuits and lock mechanism. This included the felt liner on the inside of the trunk lid. First I tested the trunk switch. I had to remove the chrome (Jaguar) trim to access the switch. It is mounted to the chrome trim plate with two screws. The switch is a very simple two wire micro switch (normally off) siliconed in place and housed in a plastic surround containing the trunk release button. It tested and worked fine between the connector located under the lid liner and the switch itself. BTW, if this switch ever failed I am pretty sure I'd be able to replace the micro switch w/o purchasing the entire part from Jaguar.
Next I tested the other end, the latch. The two wire loom teminates at the latch with another micro switch which is normally on. It too tested fine from its terminated connector to the switch. From this point, the only other loom segment in the circuit separate from the trunk loom is a about twenty inches long and completes the path from the trunk to the lid. This is a four wire loom for the trunk switch and the license lights. I did a pin to pin continuity test while I opened and closed the trunk lid. SURE ENOUGH, one wire failed intermittently.
This loom contains connectors at each end, two rubber grommets and a corregated sheath to protect the exposed wires that would show between the lid and the body. I removed the trunk end and unthreaded it from the body. After removing some electrical tape that is used in the cable's assembly I was able to slide the sheath to expose the wire segment that takes all of the movement when the trunk is opened and closed.
And here's the problem. The hot lead from the trunk lid swith in the middle segment loom has cracked from the strain. It was only being held together by the plastic sheathing. That allowed the wire to make connection occasionally. When I removed the corregated protector the wire sheath gave away making the defect very easy to find.
Here is another picture:
The cable is clearly marked with a Jaguar parts tag - part # LJE3085AB. I called my local dealer and the replacement cable part # changed to LJG3085AB, priced at $79.13 and had to be ordered with a five day delivery promise. For $80, the existing cable was an easy repair. I spliced and soldered the ends, then took up the slack of the 3 other now longer wires at the trunk connector end of the loom. Then I threaded the loom back in place inside the trunk, plugged it back in and back in operation.
I'll monitor this for awhile, expecting I'll not have a problem with it again throughout my ownership. However, if I do, I'd probably consider making this 4 wire cable myself from scratch. The rubber grommets and corregated sheath are all removable and can be used in a new loom. Connectors are common too.
On another quick note - I've purchased the Generation three secondary tensioners and cam cover gaskets. I found them at a fairly good price from Continental Imports in San Francisco. About $25 cheaper than other sources and they shipped for free. They arrived this week, so I'll be changing these out in the very near future.