Help needed with a Thermo fan

[RX MIDGET]

Hi,
After connecting an Autometer Water Temp gauge, my Davis Craig fan does not come on at all!

(Note: Tested up to 110 degrees C without it coming on - however I thought that the gauge reached the 110 degrees C alot quicker than I am used to - just 4 minutes).

The fan is wired through the supplied Autometer sender in the radiator - the gauge appears to work no dramas!

I have had a good look on the fan, but can not find an adjustment switch. Why would it need adjustment - as it worked well with the crappy old gauge???

Could the problem be the last gauge was degrees F and the new one is degrees C?

Note: I am replacing the old gauge as it was "mis-matched" with the old sender - normal driving (after 10 minutes warm up) it sat on 230 degrees F with the thermo fan coming on at 240 degrees F, ever since I have owned the car.

I am lost, any suggestions? HELP!
(RX MIDGET - 13B N/A Extend Port)

[C. Ludwig]

I would use something like this versus the little probes that you stick in the radiator fins. Drill and tap the back of the water pump below the thermostat and you're ready to go. These types of switches are available in different temp ratings. I would definitely want the fan to come on sooner than it has been in your case.

http://www.amazon.com/Sierra-TEMPERATURE-SWITCH-210-F/dp/B001RIJGPO

[t_g_farrell]

How is the fan relay wired up to operate from the temp sensor? Just the
sensor input alone won't trigger that relay I expect. There must be thermal
switch inline with the relay that needs to know the temp. Maybe when you
replaced the old setup it lost that input along the way?

[RX MIDGET]

Guys,
After talking to someone in the know, it was suggested the previous radiator may be running / switching the fan and have no gauge association. This was correct. There was a second sender (under the thermostat) driving the gauge. I put the newly purchased Autometer sender under the thermostat and returned the old sender to the radiator. The single line to the fan was power, not gauge. Presto, problem solved, so thanks guys...

[TitaniumTT]

The sensor under the thermostat is for the ECU. Is this an EFI car or a carbed car? EFI cars use that location for the ECU and the gauge pulls temp from a sender in the rear iron. Removing that sender from the ECU will result in a very poorly running engine.

Like Ludwig said, under the T-stat is the best place for it, but if you can't get there, there is a recess in the t-stat housing that I've used in the past. The problem is you won't get a trully accurate reading until the t-stat opens.