Mattt Posted October 16, 2021 Share Posted October 16, 2021 Hi all. My 85 728i BMW has just started to show its true colours. Currently the electric windows and sunroof ONLY operate with a door open. The heater no longer operates at all and the electric mirrors no longer operate at all. Does anyone have any idea on where to start with this? The fuses are fine and previous threads I've found on this issue have shown the realys to function fine, however they have not posted how the issue was solved Quote Link to comment Share on other sites More sharing options...
thegreatestben Posted October 16, 2021 Share Posted October 16, 2021 Door issue on old car sounds like loom may have fatigued. Does window performance change as you swing the door open and closed or is it when the door latches shut? 1 Quote Link to comment Share on other sites More sharing options...
Mattt Posted October 16, 2021 Author Share Posted October 16, 2021 No you can literally push on the door sensor and they stop working As soon as you let it go windows work. I have recently pulled the struts out so I'm afraid there's an issue with the boot wiring. It does seem to be an issue with bmws from time to time. Quote Link to comment Share on other sites More sharing options...
chris r Posted October 16, 2021 Share Posted October 16, 2021 I'd suggest checking/looking at the various grounds. Could be a shit connection somewhere 1 Quote Link to comment Share on other sites More sharing options...
Unclejake Posted October 16, 2021 Share Posted October 16, 2021 On most vehicles the interior courtesy lights are switched to earth, so be aware of that when you're doing your diagnostics. i.e. when the door is open the courtesy light gets an earth which completes the circuit. I suspect your sunroof and windows are finding that same earth and are missing the earth they were designed to operate from 6 Quote Link to comment Share on other sites More sharing options...
Mattt Posted October 16, 2021 Author Share Posted October 16, 2021 Thanks guys. Gives me something to look for now as a starting point. Very helpful. Quote Link to comment Share on other sites More sharing options...
Mattt Posted October 16, 2021 Author Share Posted October 16, 2021 Just moved the car. Heater works, windows work, mirrors work. This will be fun. 2 Quote Link to comment Share on other sites More sharing options...
Muncie Posted October 17, 2021 Share Posted October 17, 2021 Clear your Saturday print off your ground locations and spend the day going through the car did this on my mk4 vw golf miracles were had extra features unlocked with this one painful but rewarding task. Seriously get some sand paper and jointing compound and just go through it you'll at least be able to tick off bad earths as a fault. 1 Quote Link to comment Share on other sites More sharing options...
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