Too much heat- some notes (archive)

Inside temp sensor between pins 1 & 3 should be 33 ohms at 77F, as you say, but between 2 & 3 should be a function of temperature, per Bentley p.7-21, table c. (About 10 kohms at 77F, 35k at 32F). Pin 1 gets the GN/YL wire (12V w/ A/C on), 3 gets the BR wire (ground) and 2 goes to the temp control.

Very strange. Looks like when the A/C is on, the 33 ohms is used to heat the temp sensor. What were they thinking?

I have the BMW ETK for my car, a 1986 535i. Don't know if the heater control unit is the same as yours, but here's my interpretation of what it says:
Pin 1: (BR/GN) Heater valve control output. Ground at this pin energizes the valve, which shuts off the heat. Disconnecting the plug at the valve should therefore force maximum heat.
Pin 2: (GN/WH) 12V with ignition on, supplied by this wire via Fuse 6.
Pin 3: (BR) Ground, supplied by this wire.
Pin 4: (GN/YL) 12V when A/C is on, supplied by this wire from pin 2 of the A/C switch. This signal tells the temp control to close the heater valve.
Pin 5: (BU/YL) Temp select output. Comes right off the temp. knob control and goes to the evaporator temperature regulator, which controls the compressor clutch.
Pin 6: (BU) Interior temp input. This is connected to pin 2 of the interior temperature sensor.
Pin 7: (BU/WT) Heater core temp sensor input. See Bentley p.7-21, fig 4-7.

HTH

The inside vents are blowing hot air, checking out the Temperature control unit, have 12V between pin 2 and 3. Inside temp sensor gives 33 ohm (correct). What are the connections between Interior temperature sensor and the control unit? someone knows what is connected to pins 1-7 of temp control unit?

Bentley does not give a connection diagram.

Thanks

Luuk '84 533i

Thanks luuk

Follow Ups:

[ Follow Ups ] [ 5-series (E28) Message Board ] [ Msg. Board FAQ ]

Questions, comments, or problems, please visit the Roadfly help desk.