I cannot get the interior lights on my 1989 Abbey GT212 to work, whereas all other 12v circuits are fine. I've checked the obvious (bulbs, fuse, switch assembly)and I've done a continuity test on each set of wires between all light fittings and the connections at the control panel and have found no breaks.
However when I use the volt meter across the pins of a light fitting I get a 12.4v reading but no continuity sound. I've cleaned up the earthing connections on the control panel housing but still no joy.
Anyone got any ideas what I could try next?
Thanks
April
if they will come out make up a small loom and check the light fittings direct to your battery, this is what we do at the garage and i dont think cars and caravans are different
Quote: Originally posted by Apes on 22/5/2011
However when I use the volt meter across the pins of a light fitting I get a 12.4v reading but no continuity sound.
If your reading the voltage off the light fitting, you shouldn't expect any continuity sound as this would indicate a short circuit.
I am puzzled though; if I've read this right you are getting something like 12v at the socket, is this right? Try removing all bulbs and checking a fitting with one at a time, or as the above post has suggested, test the fitting itself.
on older vans i seam to remember that if a first in line bulb/tube has gone it breaks the circuit and the rest fail to work.try a new bulb/tube.may apply to any bulb/tube.take care with tube lights as they are boosted to 120 volts to make the tube light.this would also apply to broken earth/negative wire.Christmas lights come to mind.
------------- the only silly question is the one you do not ask.
Paul - yes I am getting 12.4v across the pins in the bulb socket. Someone at the storage site suggested it was probably an earth problem.
Michael - that may be the case, the bathroom fitting is nearest the control panel and is the only one to have a single blue wire in then 2 out, so if those tubes are blown that would make sense. Very silly set up though!
I've not got replacement tubes for these yet as they are shorter than the others, but would bridging the blue wires to bypass the bathroom fitting work to test the theory?
You need to try testing with a test light or as Michael says with a bulb and holder. A multimeter will only show you the voltage there but not current. I had it before on a vehicle where my meter showed 12 volts but my light didnt work. This would explain no continuity sound as there isnt enough current flowing down the wire.
You refer to these as tubes; are they a flourescent type lamp or conventional 12v filaments? The suggestion Michael's given makes sence and depending how many light fittings there are, the '2 out' wires could be feeding two seperate fittings, but the light fittings would usually be parallel to each other.
You generally find the internal 12v lighting is hard wired so it sounds as if you've managed to test the wiring.
If not conventional light fittings, any chance of a photo? If your not sure how to post images, you're welcome to email a photo to me and I'll post.
Quote: Originally posted by lee99780 on 23/5/2011
... This would explain no continuity sound as there isnt enough current flowing down the wire.
Continuity will test for exactly that, a near zero resistance/short circuit to indicate the wiring is intact from one point to another. I wouldn't expect there to be any continuity buzzer from the meter when checking for the voltage across the socket as this would be indicative of additional problems. You can measure for current too, but this involves cutting into the circuit and connecting the meter in series with the fitting.
You need to test the continuity at either end of the same wire, that will indicate a break in the wire or no resistance, not across both connections at the socket. You can test the voltage at the socket, it might show 12v on a multi meter but not enough ampage to light a bulb..
Thanks everyone for all the input. As suggested I made a bulb holder and checked the feeds to all the fittings. It lit up on all apart from the kitchen light, which I'm not too bothered about. Also while messing around with the bathroom fitting the flourescent tubes suddenly came on, but there was some fizzing when the tubes moved so it seems the internal connections are a bit frail as you can see!
The two filament lamp holders are obviously shot as well so given that its all old and dodgy I'm going to replace everything with LED's. At least I know the circuit's ok now so again thanks for the advice, been a good learning curve!
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