how work ect with 1 wire on a 318IS 91

[bimmer91]

hi i'm a new member and i have a problem with my 318IS 91.I dont understand how the ground work on my ect sensor.In the bentley shop manuel i have2 wire on the etc sensor but on my car i have only 1 (brown and red).how the ecm take the return signal
Thanks a lot for reply.

[DesktopDave]

Coolant temp sensor?  There are two - the single wire goes to the coolant temp gauge. Look for another one right next to it, that's the DME sensor.

[bimmer91]

tanks a lot
i will stop to loose my time on the single wire coolant temp. sensor

[DesktopDave]

Sure thing.  There is no signal on that sensor - it's just resistance. It'll have high resistance when it's cold (> 6K Ohms), dropping down as it gets hotter.  Fully warmed up it should only have 100 ohms or so.