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928s EURO '80 light lever/stalk and headlight concealing motor interaction
Hi Everyone,
I am doing some restoration work on a Euro '80 928 and recently repaired my turn signal cancellation mechanism. Today I was reinstalling the combination switch and testing everything out. I ran into some (seemingly) weird behavior: when I put my left turn signal on (ignition or no ignition) the concealing headlights start popping up and going down indefinitely until the turn signal is cancelled. I've searched the forums and found this unsolved thread describing the same problem: https://rennlist.com/forums/928-foru...g-problem.html .
After digging through the US Model 80 wiring diagrams i found a connection between the concealing headlight motor and the light switch:
Shorting the connection (56) with 12V (30) does indeed start the behaviour (headlights popping up and down indefinitely). In the short period of time I have driven this car I have not been aware of the headlights concealing motor being controlled by the light switch stalk. I only ever got them to reveal using the light switch in position 2. I have also never used high beam mode (light lever forward) and don't think I can use it as the stalk does not move and my wiring harness for the combo switch does not include the 56b pin described in thread: https://rennlist.com/forums/928-foru...cleaning.html:
Can anybody shed some light on this issue? Is there some distinction between Euro cars and US cars where US cars reveal the headlights when using the High beam / flasher? Is my car supposed to reveal the headlights when using the flasher? Is my car supposed to be able to use high beam?
I have found the solution to my issue; one of the spring loaded beams was misaligned during reassembly. This caused connection 56 and 30 to short. Why this causes the headlights to pop up and down indefinitely remains a mistery. Anyhow, realigning the spring loaded beam fixed it, works like a charm!
Also, with my turn signal cancellation "fix" I replaced the broken plastic tabs on the turn signal stalk with aluminum tabs:
the screws were sligthly too long and blocked the stalk from moving in the high beam direction. Trimmed the screws a couple of millimeters and restored the original high beam functionality; light switch in position 2 and light lever forward makes the high beams go on.
What you highlighted above was a connection between the light switch (not the combination lever switch) and the relay+headlight motor. the combination switch is between these on that schematic.
The light pods go up (and on) when the main light switch is turned to headlight mode (not markers), the headlights lights go off when you switch to marker mode, however the pods only go down when you switch the marker lights off.
What you highlighted above was a connection between the light switch (not the combination lever switch) and the relay+headlight motor. the combination switch is between these on that schematic.
Hmm I see. Still, my concealing headlight motors can be controlled using the combination switch cable by shorting connection 56 (white/black) with 30.
Yes - the combination switch's terminal (X) [which is really (56) from the light switch] and (30) should never be connected together in normal operation* - but if you do this: it activates (56) like turning the headlight on with the main light switch would, hence the motors go up. What normally keeps them in the up position is the (30b) connection from the light switch to the headlight relay - which is always on when the switch is in the headlight position. By shorting only the (56) to (30) without (30b) also on you don't have a means to keep them up hence the cycling. The headlights always cycle to park if they are the top position and (30b) is not active. This is why the pods go up when the headlights are turned on - but don't go down until the markers are turned off.
*Normal operation is either (56a) connected to nothing [stalk mid position = low beam], (56a) connected to (X) [stalk pushed = high beams] or (56a) connected to (30) - [stalk pulled to flash = high beam flash]
01-20-2020, 07:24 AM
928s EURO '80 light lever/stalk and headlight concealing motor interaction
