BMWAG
Electrical troubleshooting manual
5 Series - E34 (518i, 520i, 525td, 525tds, incl. touring) Schematics Model year 1994

Automatic heating control (HR34) - digital
Scheme 6410.1

Pin Assignment X899
PinTypeDescription/FunctionConnection
1ELeft footwell temperatureLeft footwell sensor
2ERight footwell temperatureRight footwell sensor
3ERight heat exchanger temperatureRight heat exchanger sensor
4EOutside temperatureOutside temperature sensor
5ETerminal 15Fuse
6MGroundGround connection
7ESignal, rear window defogger ONRear window defogger switch
8ASignal, rear window defogger ONRear window defogger relay
9AFunction light, rear window defoggerRear window defogger switch
10ELeft heat exchanger temperatureLeft heat exchanger sensor
11AActivation, right water valveRight water valve
12ASignal, auxiliary water pumpRelay, auxiliary water pump
13ELights, terminal 58 gDimmer
14MGroundGround connection
15AActivation, left water valveLeft water valve
16ETacho/speed signalDME control unit/DDE control unit
17M518i/t, 520i/t: not used 525td/t, 525tds/t: GroundGround connection
18not used
E = Input, A = Output, M = Ground