rear demister fault tip! very cheap fix!!!
hi all, i own a 97r 146ti, 2.0 twin spark, and having only recently bought it i do have a few small niggle to work through.
but having solved one of them, and far cheaper than my local alfa romeo agent would have you believe i thought it worth while posting.
my rear demister has never worked since recently buying it, so i got the multimeter out and started working back from the element, which had no voltage to it but perfect continuity across all routes of circuitry.
the confusing thing is that for some reason alfa chose to wire the illumination icon in the dash on the switch side of the circuit and not the load side, so although the switch works fine, the icon lights up, there is voltage at the fuse, and the element meters perfect, it still fails to operate without warning or notice from the relevant icon.
so, by process of elimination there are only two more components in sequence of the entire circuit, those being the relay located at the end of the internal drop down fuse panel in the drivers footwell, and a length of cable from the fuse panel to the element.
so, assuming without evidence of accident damage to car that the wiring loom is sound, i headed for the relay. hmmm, odd again, because you can both hear and feel it clicking, but the legs of the connections are too short for me and my domestic meter to test. so i took a chance on this relay being at fault at took it to my local againt to price up, but when they quoted me £22 for a poxy four prong relay that might take a week or two to arrive, i thought that there must be another way.
and so there is...
if you find your relay to be the fault, get yourself to Maplin Electronics and buy a N00AW automotive relay, 30A 12Vdc SPDT, for the grand total of £1.98 and bob's your uncle, a clear rear windscreen, YYYYYIPEEEEEEEE!
now when you see the relay you will perhaps be put off by the fact that this one is five prong rather than the stock four prong, but dont panic, the centre fifth prong, labeled as 87a, is for normally closed circuits and is not used and wired to in the alfa's fuse tray, and so will not be utilised within the relay either, so slot her in and away you go.
now you can again see all the other cars you're leaving behind, great...
hope a few of you find my ramblings useful.
cheers guys and gells, shrew