Sunday, July 24, 2011

Land Rover Hood Sensor - Take 2

Last weekend I figured out how to remove the alarm hood sensor. It came right out. Then I used a DMM continuity tester to see if the integral micro-switch was working. Touching the DMM leads to the contacts in the connector, I worked the switch about a dozen times by pressing on the curved metal thingy (see photo). It worked fine. So I pulled on that curved metal spring to expand it a bit, thinking that maybe it's become compressed over time from normal use. Then I reinstalled it and connected it up (removing my short circuit I'd installed a few weeks before).

Well, that lasted about a week. I returned to my car in a parking lot and unlocked it to see the lights flashing fast for 8 seconds (the manual says this happens when the alarm has been tripped). After less than a mile of driving, the "BONNET OPEN" message appeared. That went away soon enough.

It appears that the micro-switch inside the sensor might actually be faulty, resulting in intermittent failures. I've ordered a replacement sensor from an online shop. In the mean time, I've replaced my short circuit kludge.

UPDATE: Here are links to my others posts on this topic...


LR3 Hood Sensor  with actually useful photos

New links to replacement switches

4 comments:

Anonymous said...

how did you short out the hood sensor. I unplugged mine but am uncertain what to do. Thanks!

Michael said...

I used a short (0.75 inch long) piece of stranded insulated wire. I stripped both ends, then twisted the stranded ends a bit. Then shaped it into a "U" and jammed it into the connector. The stranded ends smush up against the contacts and work well. Then I taped it up with electrical tape. Eventually, I made more permanent repairs: see here.

I hope that helps.

Steve Shih said...

What would happen if I just left it unplugged? Will it damage anything?

Michael said...

Steve: It shouldn't damage anything. However, it's my understanding that the circuit needs to be completed to signal that the hood is closed. When I did my short circuit temporary fix described here, I taped up the end (to help keep the wire I had inserted from falling out) and left it hanging.