Before you read this I have resolved the problem, so I am not stuck (any more!) but if you want a diagnostic challenge & want to learn what the real fault turned out to be, so that you never get caught out, then read on!
Recently I was just about to leave a show ground, having reconnected the trailer I tested the lights. It was annoying to see that one turn light on the trailer was intermittent, although they were working fine on the towing vehicle.
When I wiggled the bulb it started flashing & continued to do so until it was turned off. But it would not start flashing again until I wiggled it in the socket or wiggled the holder.
The bulb itself was obviously working. It looked to be intact, the glass still sealed to the base, the main metal collar clean, the soldered end contact clean & prominent.
Passers-by offered two strands of advice. Either it was an earth problem from the bulb holder or it was a poor contact between the metal collar of the bulb and the socket. I had just witnessed a field repair on another vehicle were a sliver of plastic was wedged in to press the bulb more effectively against the holder & this cured his problem to get him home.
I was uncertain which category my fault fell into. All the terminals on the holder were clean & the spring for the central contact firm & clean. The earth cable was quite new & looked to make a good contact to the chassis as it was underneath the earth terminal that was supplying the sidelight that was working.
I disconnected the turn light earth wire & pulled the bulb holder out of its mounting I was able to use a screwdriver to earth it & the turn light started working. So it was clearly an earth problem, so I cut the turn light earth lead from its terminal. I stripped the insulation of the known-to-be-working earth lead of the sidelight & wrapped the strands of the turn light earth lead into it.
A slight wiggle of the bulb & it started working again. Ready to move off, no turn light. So I cleaned the metalwork of the bulb & the holder with an emery cloth. I blew out the dust & bingo it worked.
To reassure myself I ran it for a minute & it even continued to work after turning it off & on again. So I set off home.
I only went a little way, turned onto the main road & noticed that the turn light repeater light on the dash showed the trailer had failed again. Eventually I found a lay-by & all the nonsense started again.
I got my meter out & measured the correct 24 volts on the contacts. I went through all the procedures that I did at the show ground. I put another bulb in that worked but quickly blew as I didn’t realise it was a 12 volt one. I hadn’t got another 24 volt bulb but at least I knew the one I had was working.
Anyway I did eventually solve the problem, very annoyed that I wasted so much time but at least I will be prepared if it happens again & will be ready to offer show ground advice whether it is initially wanted or not!
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fv1609
Before you read this I have resolved the problem, so I am not stuck (any more!) but if you want a diagnostic challenge & want to learn what the real fault turned out to be, so that you never get caught out, then read on!
Recently I was just about to leave a show ground, having reconnected the trailer I tested the lights. It was annoying to see that one turn light on the trailer was intermittent, although they were working fine on the towing vehicle.
When I wiggled the bulb it started flashing & continued to do so until it was turned off. But it would not start flashing again until I wiggled it in the socket or wiggled the holder.
The bulb itself was obviously working. It looked to be intact, the glass still sealed to the base, the main metal collar clean, the soldered end contact clean & prominent.
Passers-by offered two strands of advice. Either it was an earth problem from the bulb holder or it was a poor contact between the metal collar of the bulb and the socket. I had just witnessed a field repair on another vehicle were a sliver of plastic was wedged in to press the bulb more effectively against the holder & this cured his problem to get him home.
I was uncertain which category my fault fell into. All the terminals on the holder were clean & the spring for the central contact firm & clean. The earth cable was quite new & looked to make a good contact to the chassis as it was underneath the earth terminal that was supplying the sidelight that was working.
I disconnected the turn light earth wire & pulled the bulb holder out of its mounting I was able to use a screwdriver to earth it & the turn light started working. So it was clearly an earth problem, so I cut the turn light earth lead from its terminal. I stripped the insulation of the known-to-be-working earth lead of the sidelight & wrapped the strands of the turn light earth lead into it.
A slight wiggle of the bulb & it started working again. Ready to move off, no turn light. So I cleaned the metalwork of the bulb & the holder with an emery cloth. I blew out the dust & bingo it worked.
To reassure myself I ran it for a minute & it even continued to work after turning it off & on again. So I set off home.
I only went a little way, turned onto the main road & noticed that the turn light repeater light on the dash showed the trailer had failed again. Eventually I found a lay-by & all the nonsense started again.
I got my meter out & measured the correct 24 volts on the contacts. I went through all the procedures that I did at the show ground. I put another bulb in that worked but quickly blew as I didn’t realise it was a 12 volt one. I hadn’t got another 24 volt bulb but at least I knew the one I had was working.
Anyway I did eventually solve the problem, very annoyed that I wasted so much time but at least I will be prepared if it happens again & will be ready to offer show ground advice whether it is initially wanted or not!
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