1986 BMW 535i Coolant Temperature Sensor?

There seems to be three coolant temperature sensors located near the thermostat housing in my 86 535i, does anyone know which does what and specifically which is the one used by the computer to set the mixture, and what the resistance reading should be ?? Car's running awfully rich -

1986 BMW 535i Coolant Temperature Sensor?malware

When you understand it, you'll see the UTTER BRILLIANCE of the design.

I owned an '82 733i and now own an '88 735i, which is virtually the identical engine that you have.

There are three levels of airflow through the radiator. The main fan is mounted on the engine. The electric fan is mounted in front the radiators (coolant and air conditioning).

The electric can be OFF, MEDIUM SPEED or HIGH SPEED.

The medium speed setting is controlled by one temp sensor. The high speed is controlled by the 2nd temp sensor.

When you cruise the interstate highway at 140mph with A/C on, you will appreciate the additional cooling range.

Incidentally, I was surprised that the transmission has one more gear than I expected. Around 82mph, it will downshift.

On my '82 I had to run wires directly from the fuse box to the alternator and various other connections because the relays were failing, one by one.

On my '88 I mostly have solder joint problems in the headlight relays and door lock problems.

Fortunately, there are excellent online forums and websites.

I bought my '82 for $600 and drove if 4 years. I thought the '88 would be nearly identical but the '82 shifted better and had a more comfortable suspension.

- CarlD

1986 BMW 535i Coolant Temperature Sensor?norton 360

It is located in thermostat housing, threaded into the housing. Color is cyan. not sure about resistance... Bentley E28 manual should have it (if you don't have the book, Get it, is worth every penny)