R129 odd lighting fault- help needed with diag.

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New Member
Oct 18, 2015
Yorkshire, UK
SL 500 1992
Hi, 1992 sl 500. All day driving lights turn on (front side, number plate, rear side lights) when car sat unused for days or weeks. No alarm fitted, keys not in. Def not leaving switch on. Runs batt flat. Had new battery. Repaired lighting monitor module (for diff issue) still doing it, I don't think it's that module. Is there a master relay for sides/daytime. Anyone else had this fault? Cheers guys. Oh btw if I reach in and turn lights on and off they all go off. Very odd. And annoying of course. Not good for my missus love of the car, lol.
Alternator relay nees checking .You may be able to remove this from the rear of the alternator yourself .Only a few screws holding it in. When you turn key on ,do you have a red charging light on?

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