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BMW E36 compact: The sunroof problem
Can online forums and DIY videos help you find mysterious defects? We check the quality of the information provided using a concrete example.
BMW E36 compact: The sunroof problem
The sunroof problem– hardly any owner of a BMW E36 from the 1990s is spared from this. Neither does the author of these lines, whose 24-year-old 316i Compact one day refuses to open the hatch to the summer sky. Pressing the toggle switch in front of the rearview mirror has no consequences; the electric sunroof doesn't move a millimeter. After five minutes of driving, another attempt and suddenly the hatch opens and closes as if nothing had happened. It's annoying, however, that the game repeats itself regularly from now on - fresh air from above remains a matter of luck.
Not a durable condition in a classic car whose air conditioning only consists of two crank windows and this sliding roof - a workshop appointment is therefore quickly arranged. The time until then is used to at least theoretically narrow down the cause of the error.
And lo and behold - exactly this sunroof problem is being discussed by some fellow sufferers in relevant online forums. There are also suggested solutions, and Two young German hobbyists demonstrate on YouTube how you can take matters into your own hands with a little skill.
My ambition as both a reporter and a hobbyist has been awakened - the matter needs to be checked.
- Flo und sein Kumpel, die sich auf ihrem Youtube-Kanal „Autonerds“ nennen, beginnen mit der Demontage der Kunststoffabdeckung unter dem Lenkstock.
Obwohl im Video am Armaturenbrett einer E36-Limousine hantiert wird, lässt sich die Abdeckung auch beim Compact durch Herausdrehen von sechs Kreuzschlitzschrauben einfach entfernen.
- Zugegeben, der Kabelsalat dahinter ist erst einmal nur verwirrend, doch zum Glück ist die Youtube-Videoanleitung recht präzise.
- Die „Autonerds“ haben das so genannte Komfortrelais als möglichen Verursacher des Schiebedachproblems ausgemacht – ein elektronischer Bauteil, der glücklicherweise mit hellblauem Plastikgehäuse aus dem Kabelsalat hervorblitzt.
- Die Demontage gelingt durch Herausziehen des Steckers, das Relais landet auf dem Basteltisch.
Das Gehäuse wird mit einem Schlitzschraubenzieher geöffnet und die kleine Platine mit der Unterseite nach oben in einen Schraubstock eingespannt, der sonst für den Modellbau verwendet wird.
- Nun werden die Lötstellen mit der Lupe untersucht, und tatsächlich fällt eine davon mit ungleichmäßig gezackten Rändern auf – im Fachjargon eine typische „kalte Lötstelle“.
- Mit einer kleinen Lötstation und einem Tropfen Lötzinn wird das etwa zwei Millimeter kleine Areal nachgelötet – fertig.
Now it gets exciting because according to “Autonerds” the problem should be solved.
Installation is easy in reverse order, then turning on the ignition, pressing the toggle switch - bingo! Sunroof open - sunroof closed - the electrics obey again at the push of a button, the error devil has disappeared.
Important NOTE
This diagnostic thriller is in no way intended to entice car owners to pull out a screwdriver themselves whenever there is a defect - after all, on cars built around 2005, even a sunroof repair can no longer be carried out without resetting a control unit.
However, there is a lively hobbyist scene surrounding the largely electronic-free youngtimers from the 1990s, who prefer to exchange their experiences with the typical weaknesses of their sometimes cult-revered metal favorites online. So if a classic car comes into the workshop, it is also worthwhile for the automotive technician to search for hidden errors on the Internet. In particular, the frequent defects in electrical systems tend to follow a certain pattern. Usually a certain cable, a switch, or a soldering point turns out to be the weakest link in the chain and is the first to give up the ghost. There's no question that conventional troubleshooting, including measuring all the cables and possibly replacing fuses, switches or cables, would have been significantly more complex in this specific case.