Switching on heater fan increases fuel and temp. readings.

[banjomandolin]

When I bought my Bis last year there were many problems to sort two of which were
(1) The lighting behind the instrument panel was not working.
(2) Switching on the interior heating fan to high speed caused both the fuel gauge and temp. gauge readings to increase, fuel by 12.5%, temp. 17%. I removed the panel and found a break in the printed circuit. When I attempted to solder across the break I managed to short circuit the wiring and blew everything away. I then fitted another panel, changed a number of dud bulbs which, although it cured the lighting problem, still left me with the problem of the increased fuel and temp. gauge readings.
Although the problem is not life threatening I would still welcome any advice anyone wishes to offer.

[126dave]

buy an aircooled........... joke,they all suffer from lecky glitches tho....lets hope poland never goes an makes an a-bomb............... :shock:

[Bruce]

italians are/were infamous for their dodgy electrics/gauges. The switches and instruments on my old Benelli 654 looked like they where made from wine gums and the speedo and tacho only gave an aprox reading due to the way the needle flapped around; Veglia, more like vauglia, used to make the prince of darkness (lucas) look positvly brilliant.

[Matt S]

Its a resistance thing causing your gauges to read high.

2 options (well 3)

1. Ignore it
2. Go through all the wiring, and i mean all, cleaning all connectors, terminals and paying special attention to earthing points
3. Check the resistance of your loom in general, once wiring gets old and has survived hot and cold extremes its internal resistance goes up considerably.  Only option in this case, replace it.

The reason your gauges show more im sure you know is that they are basically analogue resistance scales with a known calibration factor.