1986 Daihatsu Skywing - High Beam Fault Finding Tactics

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Thu 4 Nov 2021 00:27
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - edlithgow

No High Beams

Both bulbs probably didn't blow. Could be wiring or a relay (though none is shown on the circuit diagram I have) but its most likely to be a failure of the "Multi-use"" steering column stalk switch unit, which seems pretty fragile.

Skywing seems to be a mix of Charade G10 and G11 bits, with emphasis on the latter. I only have the circuit diagrams for the G100, but its probably very similar

It has a required connectivity diagram for the switch connector block for the (presumed) headlight switch positions HF, HL and HJ involving connections HM, HS, E, TB, S, D, D2, B1, +2, R, +1, WB, WS, F, F1, HO, INT, B2, D1

There is NO KEY for any of these abbreviations (though some of the meanings are guessable) rendering this "information" spectacularly b***** useless to me.

ZE PLAN, such as it is, would involve attacking the car side of the switch connector block, jumpering connectors together until hopefully I find the ones that make the high beams come on. The corresponding switch side contacts will then be the ones connected to the faulty bit of the switch.

Does this make sense?

I'm wondering if I need to try and buy or improvise in-line fuse protection for my jumper leads. Since the currents involved are normally carried by the switch perhaps I can assume they wont be too damaging, even with likely mis-connection?

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Thu 4 Nov 2021 09:17
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - elekie&a/c doctor
I would start by checking both bulbs . Does the hi beam warning light illuminate on the dash when main selected? If it does , then it’s unlikely to be the combination switch . No idea of wiring diagram .
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Thu 4 Nov 2021 10:07
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - bathtub tom

Does the headlamp flasher work (has it even got one)? If it does then I'd start by ruling out the stalk and perhaps work back from the lamps.

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Sat 6 Nov 2021 02:52
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - edlithgow

No high beam dash indicator or flasher function, and I can't feel the detent for the high beam position on the switch-stalk.

Pretty sure its the switch, but I will try and test the lights independently first.

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Sat 6 Nov 2021 08:49
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - edlithgow

Seems I was misinterpreting the fault.

The (iodine discharge, I think) bulb has a three tab connector, seems to be earth at the top, and two +, I only get BOTH the positives live, so I guess I've only got full beam, no dip.

Unfortunately this seems to indicate a switch fault since the ciircuits seem to be intact

The bulb is OK when jumpered directly from the battery (both elements)

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Sat 6 Nov 2021 09:12
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - elekie&a/c doctor
Looks like you’ve got a switched earth headlight circuit, commonly used on Jap cars in the 80s-90s . Circuit works back to front to what you think . The main beam circuit is made across the 2 outside (vertical) terminals of the bulb .

Edited by elekie&a/c doctor on 06/11/2021 at 09:14

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Sun 7 Nov 2021 02:04
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - edlithgow
Thanks. That seems consistent with observation. The presumed earth is only an earth (only lights a test light connected to bat + ) in the main beam position so I guess its switched.
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Mon 8 Nov 2021 02:49
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - edlithgow

I have a spare used switch that looks in better condition than the one that is in place, and tried plugging it in to the multi-connection block without a full install (VERY difficult to remove – memo to self – cut off ALL barb connectors without mercy) but only some functions work in that mode. I dunno if this was due to it lacking connections through the steering column, say, or it being broken, so it wasn’t an interpretable test.

The problem seems to be primarily mechanical.

My recollection is that one switched between dip and main beam by pulling the indicator/lights stalk toward you, but none of the 3 switch units I have (The original-to-me that I broke by spraying contact cleaner on it, the one fitted on the car about a year ago by a Taiwanese mechanic because I was short of time, or the above spare, seem to have fore and aft movement of the stalk. Seems a bit unlikely that they ALL have jammed, but it looks that way at the moment.

The switch unit on the car is loose, allowing a bit of rotation of the whole thing. There are holes in its plastic frame that look intended to take securing screws or bolts, but nothing to screw them into.

Before I got it this vehicle had apparently been professionally maintained by Taiwanese mechanics its whole life, so atrocities seem quite likely.

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Mon 8 Nov 2021 11:30
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - edlithgow

Gave up and put it back together. Tricky to get the cover aligned properly but removing the seat helped, and I replaced some missing screws so its not as loose as the previous professional version.

Decided to chance my arm putting it in for inspection just before closing time, when they'd be rushing. I left a dud reversing light as a distractor.

The only concrete result of my fiddling about seems to be the indicators no longer self-cancel reliably.

PASS!

Either they missed it, dip beam isn't part of the test, or there is now a knack to getting it that I don't have.

There is a theory that foreigners are more likely to get a pass because its a PITA to explain a fail to them, so maybe my failure to learn Chinese bears fruit, though I have had a couple of fails in the past.

Doesn't seem especially dazzling, possibly because the bulbs are weak/old. Could possibly address the practical problem with supplementary lighting, but might not be so lucky with the next inspection in 6 months time

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Fri 12 Nov 2021 23:17
1986 Daihatsu Skywing - High Beam Fault Finding Tactics - edlithgow

Turns out if you REALLY force it to what feels like pretty close to stalk-breaking point (tested on the least good off-car spare only so far) you can get fore and aft movement of the stalk.

I'm thinking some lubrication might help, but I'm a bit leery of spraying stuff with a solvent carrier on it after contact cleaner seemed to embrittle the plastic on the first one.

Maybe a "dry" silicone spray as recommended recently for seatbelts would be harmless?. I THINK I've seen 3M stuff here.

Failing that I have some silicon grease I use as brake grease which I might be able to work in with a toothpick or similar.

Suggestions?

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