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View Full Version : Trunk lamp shorted out, tried everything...



Magna_Lad
20-09-2014, 12:26 AM
Hey peeps! So i shorted out my trunk lamp installing a neon. Ive read all the posts about fuses, checked all the fuses inside, all good, checked fuse 10 and 11 in engine bay all good... everything is working (as in all lights both interior and exterior) EXCEPT THE TRUNK LAMP! Is there something im missing?

Remote boot release is working, indicators, dash, radio, ciggy lighter, clock, aircon, heater, wipers, all headlights, tails, plate lights, brakes all gd, tried several bulbs in trunk and nothing...

Any suggestions appreciated as Im outts ideas :)

Cheers all

Magna_Lad
20-09-2014, 03:20 AM
Ok did some more research for TJ Magnas...

Im assuming its not a fuse issue as everything is working fine apart from the trunk lamp. Plus, correct me of im wrong, but the tail lights are working and that runs on the same relay as the trunk lamp, so its not a relay issue... so Im thinking it must be a wiring issue between the trunk lamp and the switch...

Anything I should look for inparticular? Is it likely that shorting the light out maybe burnt out some wires?

Cheers

Magna_Lad
20-09-2014, 11:10 AM
So, rather surprisingly, my neon wasnt blown, checked and all good... Im now thinking its an issue between the light housing and the connector on the side wall near the boot hinge. I think theres power to the switch on the trunk latch because i wiggled the wire (+) and mechanism around and the alarm went off (after remote opening the trunk). Im also wondering if theres a good connection in the light switch, looking at it, im not convinced that theyre touching but cant get my fingers in there. Could a short be strong enough to make the grounded metal element move away from the positive coils? By this i mean, i noticed that the positive element was wire coiled around a plastic stop, which the negative element (a metal tongue) is forced onto the coils, thus making the connection...

Time to find my multimeter me thinks!

Also is this switch on the trunk latch with +/- WIRES on passenger side of latch, definitely the trunk lamp switch, or is it part of the remote open mechanism? I noticed theres a wire connectef to the trunk key barrel so was thinking that the remote switch is either part of the barrel, or connected to the wire coming off it...

Cheers!

Magna_Lad
21-09-2014, 07:08 AM
OK, if youve gotten this far in my own little personal convo... prepare to be truly amazed!! Is it correct then, that the mechanism in the trunk latch, when the two elements are engaged (trunk open) that this completes the "grounded" connection for the trunk lamp? I previously thought it was for the positive somehow but found on closer inspection, theres no charge going to either of the elements... and that the trunk lamp housing connector has power going to it still... Inside the latch, the element attached to it would def have to be negative as it is by nature of position... grounded! Makes no sense to have a postive feed (wire going to second - lower - element inside latch) going into a negative enviroment... so this must be the negative to the lamp housing?

So latch switch is to complete the negative circuit only? Ok, so narrowed it down further to the grounded wire, ill check to make sure the latch elements are connecting, maybe the "short" left the already limited connection spot, unserviceable... then ill check the wire coming off the latch, maybe it died somewhere...

Cheers!

Ensoniq5
21-09-2014, 07:22 AM
According to the TH/TJ manual it's a basic earth-switching setup. Power is sourced via a 15A fuse in the relay box, via the junction box to the lamp (red/blue wire). A green/blue wire runs from the other side of the lamp to the switch (basic on/off SPST), which is earthed. Closing the switch provides the lamp with an earth, completing the circuit. I've not seen the physical setup (mine's a wagon anyway) so can't comment on what things look like.

I would perform two tests with your multimeter (if you haven't already). 1: Test for +12V at the lamp holder at one of the lamp's terminals. If no power, the fault is upstream of the boot lamp & switch. 2: Check for continuity between the other lamp terminal and a good earth point with the switch closed, and no continuity with it open. Not sure if this is possible without actually closing the boot as I don't know what the setup looks like. If both tests are positive then the issue is with the lamp or it's connectivity with the lamp terminals.

Magna_Lad
22-09-2014, 10:32 PM
Thanks for the info mate. Theres def a positive charge at the lamp housing, didnt have my multimeter, misplaced it somewhere so couldnt check for continuity... following the grounded wire from the lamp housing became a nightmare as it disapeared somewhere between the parcel shelf and back.seat, so i gave up lol got to frustrating! Was thinking of just running an auxillary wire to the switch, so much easier, at least that way i can test if it a problem with the switch connection.

Will def get to it though. Thanks again mate, appreciate you taking the time to look the info up and pass it on!

Magna_Lad
24-09-2014, 01:47 PM
Found that the switch itself isnt grounded... so i improvised. There was a grounded wire nearby on the trunk lid, so i ran a wire from this to the metal arm that run from the key barrel... Im guessing that the earth connection comes from the key barrel to complete the circuit. Doesnt seem to be a problem with the remote unlock, so ill see how this works. Seems to be fine so far and I now have my undercar LEDs hooked up to the trunk lamp circuit.

Too old now for LEDs while I drive around, but a shame to let them go to the wreckers with my old TS. Cant beleive they still worked after 5 years of just sitting under the car!!

Cheers