This is a collection of information to assist in fault finding and sourcing alternative parts. The Tridon Info pdf on the alternative parts page has fault finding information for some sensors.
BMW Part No 13 62 1 739 510 Air Temperature Sensor
It is also used on many E36/38/39/46 series cars and other bike models.
An Alternative is - Airtex 5S1006,
Airtex Vehicle Electronics
The sensor needs cleaning periodically, At each service would be ideal.
BMW Part No 13 62 1 703 993 is listed as a Double Temperature Switch. It is actually a double sensor and only one sensor is used. The second sensor can be connected to a gauge. It is used on many E36/38/39 series cars 1998 onwards.The socket is BMW 12521703571 and pins are 61130007657 (car parts).
BMW Part No 11 78 7 685 320 Oxygen Sensor.
Currently listed as an NGK 6 Ohm (NTK 28028) NGK Info PDF
BMW Part No 13 63 1 436 000 - It is common to the E36 318i and Z3 cars
It is actually a Throttle Valve Position Sensor (TPS).
Used parts can be picked up on EBay
BMW Part No 13 53 2 345 868 - 00-04, 13 53 7 679 998 - 05-07 / X / G Series.
The idle actuator is a stepper motor, 00-04 has ?? steps, 05-12 has 64 steps
BMW list it as Part No 12 63 7 689 965 Oil Pressure Switch - M12x1.5mm for all singles (CS/GS/G650GS/X650).
It requires a 90 degree adaptor on the F650GS/CS and is shown without the adaptor on the newer G/X models.
The switch is Normally Closed and operates at 0.3 - 0.6 bar
Adaptor Part No's are :
61 12 7 695 204 - Repair Line, Oil Pressure Switch $US26
11 11 7 695 425 - Adapter Oil Pressure Switch $US33
The general consensus on the engine casing thread is:F650GS 2000-2005 - M10 x 1.0mm - in original location - (Use adaptor with new BMW Part or the F650 Sensor)
1/ A little dirt/oil residue in the switch can cause the dash lamp to light at idle. Clean it before replacing.
2/ More information on alternative part sources is needed. Any additional information would be welcomed.
3/ The cost of the BMW adaptor and wiring repair lead adds complexity and makes purchase of it uneconomic.
4/ Possible alternatives for the F650GS/CS are Autozone Parts PS177, OP25511, Airtex PS177.
5/ Replacements in Oz/NZ - Tridon TPS021 (M10x1mm Single Connector) - TPS039 (M12x1.5mm 2 pin connector)
6/ BMW F650 Oil Switch Part No 12 63 7 670 015 - Oil Pressure Switch $US16 (Same price as the GS switch)
7/ The Tridon catalogue on the alternative parts page has test procedures for some sensors & switches.