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Lupo Number Plate Lights


dommatthews
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You have a short in that circuit,

so you need a meter with a continuity function, start with lamp holders, unhook them then test the supply wires to ground with the contnuity test to see whic one has the short in it. You need the wiring diagram to see where you need to go in the loom.

One place to look is the boot hinge, the edge may have worn through the loom there

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Without a multi meter it's difficult to fix this kind of fault, Power can't flow through a dead fuse, the fuse blows to stop the wiring from catching fire. I know, someone replaced a 5amp with a 25amp and the wiring loom melted I had to rebuild the whole thing

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No don't put a new fuse in, find the fault before you do that.

Using the meter to find the problem, test the meter first, set to continuity test, in this mode the meter puts out a small voltage to test for a connection between two points so if you touch the meter probes together you should get a tone from the meter indicating there is a connection.

In your problem you have a short ie a connection between two points that should not exist, there are two kinds of wires, feed wires that supply 12v or signals and gound wires that complete the circuit sometimes the car body acts as ground. Somehow your feed wire to you number plate lamps has become connectd to ground when it should not be

Start with the numberplate lights, remove the lampholders and the lamps

Test 1 is the short in the lamp holders, remove one of the wires from the lampholders, if you have two remove the same wire from both, put the meter probes where the lamp would go, if you get a tone the fault is in the lampholder.

Test 2 is the short in the wiring, Connect one probe to the wire you removed, the other to the lampholder where the lamp would go as before probe both of the lamp connections if you get tone on one and not the other then the fault is in the wiring repeat the test on the other lampholder.

If the fault is in the wiring then you need to follw the wires back into the car ELSA WIN can guide you as to wire colours to look for

the most likely problem is an insulation failure where the wires pass through a hole in the body shell just a bit difficult to find.

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I tested bulbs inside the holders, then I removed the housing for the holders from the wires and tested them they were all ok. I then plugged one back in then put the put the probes into the other two(other connection point for housing) and there was a reading. I'm happy to take pictures

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Ok looked at the diagram, looks like this

12v ----- E1 light switch ---grey + green ----(A) 5amp fuse (B)---grey + green--------(e)--Lamp 1 -(f)------brown wire ----- Ground

|--------© Lamp 2 -(d)-----brown wire ------- Ground

There are 6 points for testing A,B,c,d,e and f

Ensure light switch is turned off, remove the fuse and Lamp 1 and 2, this isolates the wiring, test for contuity between ground ( the brown wire ) and © and (e) if you get both the fault is in the wire between B and e or c

THanks for your post please describe where you get the reading using the above diagram, please note bulbs (lamps) can't be tested in place as to the tester they look like the wiring short we are looking for.

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To start with I have tested the lamp holders and everything is reading there - http://imgur.com/hfbpp20

Then I tested the brown (ground) of the left side to the ground of the right side this feeded nothing back. Same with the green and grey.- http://imgur.com/fGMs94I

http://imgur.com/URLaiKb

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Thanks for the pictures:

The second picture shows a plug with brown and grey green cable, if there no comtinuity between those two grey green and brown plug terminals when you tested it we can move on to another test.

don't plug in the lampholders, put a fuse in, 5 amp, then turn on the lights and check for 12v dc between the grey green and brown wires in the plug. Be careful checking or you will blow the fuse yourself

If you get 12v and the fuse doesn't blow then the problem is in the lampholders

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yep when putting probes onto the greeen/grey and brown there is nothing there.

so next step would be to put a fuse in (5amp) then check the same again on both sides? is that correct?

if so do i need to leave the other one without the lamp holder connected?

and also am i checking continuity?

thanks

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Disconnect both lampholders so you only have the plugs

Put the 5amp fuse in, turn on the lights

Check for voltage NOT continuity between grey/green and brown in the plugs.

If the wiring is OK then you should see 12v on both plugs, if the fuse blows then there is still a fault in the wiring

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Well done that's really good so the fault is in one or both lampholders, from your picture it looks like self tapping screws holding them together, time to take them apart.

Remove the screws, that should remove the cover and expose the lamp ( bulb ) remove the lamp and repeat the contunity test on both lampholders.

If they both test out OK as no continuity between the pins where the plug connects, replace both the lamps

If there is continuity with the lamps removed then replace the affected lampholder

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DONE! There was an LED in one bulb where there was no continuity going through, where as the other light had a standerd bulb in and there was a reading! I then put another standerd one in and boom there was a reading! Put them back into the car popped the fuse is and turned on the lights. No blow. I checked the lights and was so happy! Something so stupid was really bugging me!

I really appreciate your help Carrera! Wouldn't have been able to find that if it was me trying. Thanks so much!

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