A tale of two problems solved
I always read the Letters and Tech Help sections, hoping to come across some information that could ultimately be of use. Occasionally, I spot something that resembles a problem I’ve had and found an answer to.
After coming back from a two-month, 5,000-mile trip, I came home to several unread copies of MMM (my wife has a subscription).
Low and behold, in the Tech Help section I came across two problems I have encountered on my 2015 Itineo FB600 Fiat Ducato A-class.
Like Steve Bovey (Summer, p114) I had intermittent warnings about ‘check RS indicator’.
The turn signal clicker would speed up (as if a bulb had gone) yet the indicators would be working OK externally when I checked.
I eventually traced the fault to failure of the ballast resistor strapped across the Jokon LED rear indicator lamp assembly. On my Itineo, both Jokon LED indicators had high-wattage resistors wired in parallel, which were not very well protected from the elements and the ends had corroded.
These resistors make the CAN bus think that these are ordinary bulbs (21W) not LED (2-3W). One would think that these days the on-board computer would be able to be programmed to accept LEDs!
I suspect that Mr Bovey has the same problem. Jokon does make a control box for LED lights (62.3001.032) but I would be surprised if this is fitted – being quite expensive. In my case, I bought a couple of high-Watt 8ohm (Ω) resistors (such as 100W8R0 from
cricklewoodelectronics. com for £4.20 each), screwed them to a heat-sink/mounting plate and found somewhere more protected to mount them on the chassis.
Also, I had the same problem as Steve Cocker (in the same edition, p115) where my thermometer wouldn’t show a temperature at all, just ‘---’.
My A-class has bespoke mirrors and the thermistor is not in the mirror, but the cabling connections into the Fiat loom are close to the fresh air vent that is closest to the driver’s window.
There was no problem with cabling or connections; the thermistor had been damaged by water ingress. The thermistor itself was found to be sited low down at the front of the engine bay – not easy to find.
The thermistor is
10kΩ@25C NTC. These are very cheap and easily obtained by Googling ‘10k NTC thermistor beads’. Mine cost 72p from the above website, but there are lots of other sites to choose from, with some offering waterproof and cabled devices.
NTC stands for Negative Temperature Coefficient so, as the temperature rises the resistance falls, so a display showing high temperatures is unlikely to be caused by poor/ dirty connections. I hope this may be of some use.
Don Oxley