Spider Electrical Issue

A couple of quick questions that an Alfa electrical boffin can probably help answer.
1977 Spider 2000, UK spec.

Fuse no. 4 is listed on schematics as "Main Devices". Studying the diagram, I cannot see any device which would draw power at standby (vehicle off, keys out). When I go to replace the fuse, it arcs, which seems to me to indicate something in that circuit is 'on' and drawing power - any thoughts as to what the offending item might be ? It would appear to feed the headlamp stalk only (via a 2.5mm gage wire, so heavy current draw...) All lights are off durng this process, incidently.

Fuses in general - I have seen indications that ALL fuses in the block should be 8 amp - the fuse I am replacing was a black i.e. 25 amp fuse - can anyone confirm correct ratings for the fuses in this block ? Some of the connections are 1.5mm wire, others are 2.5 - would the large gage wire connections require heavier duty fuses, as a general rule ?

Thanks

Unfortunately, I have only a 1972 diagram that does not show any connections to fuse #4. Would it be possible for you to scan and email me your 77 diagram so I could study it?

Sorry for the delay in responding, I have been travelling non-stop lately, and am well-behind with correspondence.
I noticed that this car has an extra rubber knob next to the hazard switch on center console - from correspondence that came with the car, it may be a Bosch intermittent wiper control (which doesn't work anyhow !) I am going to wire around this, to get things back to 'original' spec, and see how we get on. As to the schematic, I'll try and scan it and email to you this weekend, so you can have a look.

Does your car have bonnet or boot lights? Might be worth checking that they're not staying on. Not that there could really be anything wrong with Italian wiring systems of course........!

Andy, I busted the underbonnet light while cleaning engine compartment, so it's KO...the boot light has already been removed (had similar problem with an MGB before, so I learned that lesson !!)
I replaced all 3 of the console switches, using wiring diagram from Papajam (thanks again for that). At same time, I also removed an aftermarket Bosch intermittent wiper control, to get things back to 'stock' config.
Now, instrument lights work OK via switch, but heater blower and wipers are not yet functioning. Fuses all OK, all wires correctly connected at switches, and at blower and wiper motor.
The mystery connection at fuse 4 turned out to be aftermarket radio power.
Previous wiper switch was internally jumpered between 2,4 and 6 -had to make wire/terminal ass'y to connect these terminals on the replacement switch.
Hmmm.....

This is really winding me up now...
Replaced all 3 console switches, carefully checking connections at switches per schematic. All OK.
Replaced column switch stalks as well with new part, wired in correctly per schematic.
Checked all connections at fuse block - all is as it should be per schematic.
At this point, I get blower light in speedo, both low and high settings, but no blower.
Wipers are not functioning at all.
Indicators do not work either, but flashers work OK.
Headlights work OK, both dipped and main beam.
Every time I replace the fuse controlling wipers, it pops as soon as battery is re-connected.
Wiper motor was not disturbed, and was working OK last fall.
I am wondering if something was disturbed at ignition switch when I removed column shroud - does anyone have a photo or some indication as to what lead connect to which terminals at back of ignition switch ? I see schematic shows only Black 12ga wire to Term 50, brown to Term 15/54, and red 12 ga wire to Term 30, but I see many empty terminals, and cannot tell which terminal is which on the switch itself (crap eyesight, I'm afraid). Can anyone guide me, as I look at the back of the switch, which of these leads connects to which terminal ??
Running out of ideas. Don't think the wiper motor was drowned in scuttle, as drain hole is clear (and car was never in rain).
HELP !

With regards to the question on fuses I raised this recently and the conclusion was that all fuses should be 8 amp.

I assume your car has a foot operated manual washer switch, apparently this is also a key element of the wiper wiring. I have been told by people 'expert' in these matters that problems with the wipers can be traced back to the washer switch wiring.

I still can't get over that it is possible to walk away from the Spider, clutching the ignition key with all of the electrical items still on, especially heater fans etc.

Anyway best of luck.

agreed, this is a looney way of wiring a car...
I checked the wiper wash switch on floor - all wired correctly, and continuity through switch checks out...but I'll give it another look.
I am going to try hot wire direct to wiper motor to see if it runs or not later today, now that I have cowl off...thanks for the input.

Thanks for the diagram, garwood!

A quick look at it reveals that the brake lights are on the same #2 fuse as the wipers. I would first disconnect the white wire at the brakelight switch and see if the fuse blows. If not, the problem is in the brakelight circuit. If it does blow, we'll continue with the wipers.

Blower; with the switch off, reach in through the floor duct with a pencil (or similar) and try to spin the fan. Does it spin?

Not sure the difference between indicators and flashers. Could you please explain?

Indicators = direction indicators (turn signals)
Flashers = hazard lights
Checked brake light switch - disconnecting made no difference.
Hazards work OK. Indicators do not work at all.
Wiper motor works with direct power applied to slow and fast terminals on its multiplug. Also works with power directly applied at switch terminals. But does not work when switch is operated. On High setting, fuse blows.
Floor switch is OK, properly connected and functioning. Tried jumpering 1 and 2 (white/blue wires) but made no difference.
In the process, I found damage to main positive cable at battery, which has now been repaired.
Re-checked wiring to all 3 console rocker switches - correct per schematic.
Checked wiring at fusebox -all appears correct.
Ignition switch wired correctly - saw back with aid of light and mirror !
Re blower, cannot seem to reach the blower wheel - should it be accesible from bottom of case ? What is its orientation (i.e., is blower axis vertical or horizontal ?)
Have trolled the archive, but am running out of ideas. Even an automotive sparky who spent 2 hrs looking is stumped....Any diagnostic tests anyone can recommend to pinpoint the problem ?

My Isle of Man tour this weekend is looking bad...might end up having to take the Mazda instead..(yawn)...

SUCCESS !!!!! (sort-of)

So happy at the moment, I could dance on the ceiling.
After 4+ months of wrestling, I now have fully functioning systems on the car. Wipers, indicators, instrument lights, boot light, glovebox light, etc etc....it is so damn exciting, I can hardly stand it.
After studying the schematic supplied by the factory, and reviewing the copious materials I downloaded from this BB, I discovered that by reversing the leads to terminals 1 and 8 on the wiper switch, that everything returned to operation. I still cannot fathom why, as this does not match the schematic - and all other wires throughout these circuits ARE to the schematic. Some day, when it's a bit warmer and brighter, I'll get back under the dash and have another look, and hopefully solve the mystery for good. Meanwhile, as it all seems to be working well, and weather permitting (??? ) it's off to the Isle of Man on Sunday !!! Wish me well. And thanks for letting me vent (in a positive way). And also thanks for all the help and support....this BB is the business !