Ahmedsinc 414 Report post Posted October 2, 2011 Hey all Within the past two months my partner commented on a peculiar 'burnt' smell in the cabin of our 325i. The odour seemed to subiside after about 48 hours and so far has not returned. Oddly enough there are three LEDs that occasionally stay illuminated on the recirc, a/c and rear demister buttons. It doesn't have any regular pattern to when the lights stay on, but the heater keeps flowing hot air irrespective of what position the temp dials are set to. This wasn't much of an issue in winter but as summer appraoches I'd really like to get this one sussed out. The heater blower still functions fine and dandy but I'm getting well sick of having to dirve around with all windows open in Aucklands shite spring weather Any suggestions to where I should start hunting for faults? Quote Share this post Link to post Share on other sites
BM WORLD 1283 Report post Posted October 2, 2011 (edited) swap the heater control panel out for another good one. also is the fan working?? fan resistor ?? also replace the micro cabin filter in the side of the heater box also your heater tap could need replacing . have all the parts Edited October 2, 2011 by Brent HARTGE535i Quote Share this post Link to post Share on other sites
polley 916 Report post Posted October 2, 2011 It is common for a capacitor to crap out in these units which will cause them to do weird things, turn on/off by them selves, fan staying on etc. It costs approx $1 in parts to fix if you're handy with a soldering iron. But this would not account for the burnt smell. Quote Share this post Link to post Share on other sites
JaseNZ 53 Report post Posted October 2, 2011 sounds like the fsu to me , When these go the system defaults to fail safe and just blows hot air all the time no matter what. This is a common problem and could be your fault. Quote Share this post Link to post Share on other sites
Ahmedsinc 414 Report post Posted October 2, 2011 Gah!!! There goes my week off! Thanks for the suggestions gentlemen Quote Share this post Link to post Share on other sites
DrphTa 5 Report post Posted October 3, 2011 While on this topic. When I push my windscreen button to demist, the fan goes to full speed by itself. Once I then turn the fan speed down, the windscreen button clicks off. Capacitor problem? Quote Share this post Link to post Share on other sites
JFry 1 Report post Posted October 3, 2011 ^Thats what it is supposed to do, assuming yours is the digital one. Quote Share this post Link to post Share on other sites
DrphTa 5 Report post Posted October 4, 2011 Bit silly dont you think? Why would want it on full speed all the time :S Quote Share this post Link to post Share on other sites
Ahmedsinc 414 Report post Posted October 6, 2011 OK, so further things to scratch your heads over! Replaced the control panel on Wed (Thanks Brent!) with a good unit, resulted in no change. Recirc, a/c switch and rear demist buttons still don't light up or function and we're still flowing nothing but hot air into the cabin. Have done a little googling on the matter and have found threads blaming the heater control valve AND the heater taps. Going by what I've seen so far the likelihood is the control valve, though I am starting to tire with buying parts that may or may not cure the problem. As a footnote I have replaced the thermostat, thermo housing, water pump, viscous fan coupling and a new all alloy radiator inside the last 8 weeks - the heater has only started faulting since then - any correlation? Fuses are all good, and I'm assuming the relays are too. Any suggestions would be greatly appreciated Quote Share this post Link to post Share on other sites
