The clue is in the lamp type code as in the picture
Lamps ending in "S" are for Projector based systems - including Volvo's ABL
Lamps ending in "R" are for Reflector based systems - which was early XC90
And with the lamps ending in "S" - those with an odd number (1 and 3) have also an integral ignitor circuit (hence the larger base), the even number lamps (2 and 4) rely on the ballast having an ignitor function (a bit like the starter switch on the older type fluorescent lamps).
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2011 XC90 D5 Executive
2003 C70 T5 GT
2012 Ford Ranger XL SC
1977 Triumph Spitfire 1500
1976 Massey Ferguson 135
Last edited by Tannaton; Feb 21st, 2018 at 15:39.
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