74 europa fan switch question

[xaplax101]

can anyone help with this?..........we know that fan works because we power it directly but doesn't come on automatically when the engine gets hot......these 2 switches are attached to the rear of the thermostat housing in contact with the coolant......no idea what the silver one labeled DR699 is. the other one seems to be a normal thermocouple......the resistance cold is 850 OHMS colds and drops to zero when we heat it with a hair dryer......is it for the temp gauge in the dash? the silver one does not respond to heat.....any ideas?
thanks
ted

[dakazman]

  What color wires go to these items?
 You can trace their usage here:

http://www.lotus-europa.com/manuals/misc/electrical/spclc.gif

 I may have the wrong schematic shown but you can access them all here:

https://www.lotuseuropa.org/LotusForum/index.php?board=20.0

Dakazman

[4129R]

The fan is turned on by an otter switch set in a rubber grommet in the right side of the radiator near the two hose connections.

When it gets up to temperature it earths the fan motor and causes the fan to work.

I have never seen anything like your photos on any TC or TCS from 1972-1974 models.

[BDA]

  xaplax101!!

Look for black/green and yellow/green wires around the radiator and check the wiring diagram to see how it’s supposed to all connect together. Likely you’ll have to at least get another method of turning on the fan at the proper time and back out the switches the DPO left you with.

Good luck and keep us informed!

[Dilkris]

Not too sure what you actually have there.
Please see photo of temp sender I have just photographed on my TCS.
Can you post further pictures of DR699? What is the white affair on the top? Some kind of electrical connector? ( It looks like a pressure sender to me )
I honestly don't understand why someone would want 2 senders at this location - as 4129R points out the switch (otter switch for the electric fan) is mounted into the side of the radiator.
What ever they do or are supposed to do, be careful with that copious use of PTF tape on those threads, those senders have to earth to the chassis.