Hi all, I don't think it is relevant but truck is a 2015 Iveco Eurocargo. I bought it used 18 months ago with 60,000km. The original owner had fitted led rear lights and had also not wired them into a dedicated harness offshoot which was required. When I bought it, the truck was throwing fault codes as it didn't recognize the led's due to insufficient current draw. I rewired it through the trucks wiring harness and rather than add resisters to the led's so the truck would recognize them decided to wire in series another set of incandescent rear lights and mount these higher. (Body fitted is a beavertail, so led's were down low). Anyway after that got rid of all error codes and truck recognized lights and problem was fixed or so I thought. Truck is used for relatively infrequent moderate length trips mainly at night. Each trip is about 400km in length and truck might stop engine once in that trip. No idling, just start, drive, stop. I started blowing bulbs mainly drivers side and relatively evenly distributed between stop/tail/indicator bulbs. I blamed my wiring initially and have since rewired not just my additional lights but also the led's. Have since rewired a third time just a completely rule out. Tail light assemblies and bulbs are Narva's which i don't believe to be a cheap rubbish brand. There is no common time or place which the bulbs blow, may last the entire 400km trip, or may replace one that blew through the trip at the workshop and then when I back the truck out it may blow again . This has happened twice now and was an indicator bulb so not even activated before it blew. I thought it may be an earthing issue, as I had earthed it through the harness, so I also earthed it direct to chassis. As well as cleaning all other earthing points, neg battery cable, harness earth etc. Again I thought I had it fixed, with no blown bulbs in probably 5 or 6 trips, but have recently started blowing them again. For reference earth cleaning etc was only done about 3 weeks ago so would think unlikely that bad earth could be problem again. Sorry about the long winded post but thought I should try and cover all symptoms/problems. Any idea's? Has been to dealers for other stuff (def issues) told them about it. They said cheap bulbs (no), then severe movement damage (mounted on drop down ramps) (no, ramps are lowered and raised by hand, e.g. me, also as above bulbs have blown numerous times without ramps being moved). Then they said just put resisters with the led's. They do have a point it would fix the symptom, but am I just being stubborn wanting to get things to work right? It shouldn't be blowing bulbs. Thanks Brett
Blowing filament bulbs is either mechanical (vibration or shock) or electrical (high voltage) As you ruled out mechanical … get a DVM with a hold feature and measure the max high voltage over time. One more thing... Do you have electric motors that run and shut off ? Lift gate, winch, etc … Like an ignition coil, when a magnetic field of a motor collapses it sends a high voltage spike back through the supply.
I worked in a fleet years ago and started going through bulbs like that. Yes they were a top name brand. We finally changed brands and the problem went away.
Thanks guys. My initial thoughts were also high voltage or spikes but talking to a mechanic he suggested an earthing problem but I think I have also eliminated.that. Just checking my notes again, over the last 13 bulbs that have blown 12 have been in the rear drivers side assembly and 1 in the rear passenger side assembly. None of the front bulbs (which are factory incandescent) have blown since I have owned it. Would voltage spikes etc be location specific? No electric motors apart from factory one's such as power windows, def motor, windshield washers, etc that I can think of. Again nothing I can correlate to timings of the bulbs. I will research a quality alternative bulb and see what I can find, nothing to lose that way at least, they can't blow any faster than the current ones. Thanks again gentleman.
Decided to wire in new tail light assemblies (incandescent to replace the Narva incandescent) as I had a set of new take offs from a Scania in the shed. We'll see if that makes any difference.
Just an update. Appeared the scania taillight assemblies fixed the problem, 4 trips and no blown bulbs. I'm a happy man, apart from the new issue with the transmission. See other post. Thanks
Good to hear you got it fixed... for now They make computer 'safe' led's also... or whatever they call them that don't show up as a burned out incandescent.