absolutely!
we actually run 40 amp fans so hot through sensor is no good!
to be clear— at shop we run green wire from coil to fuse to sensor.
from sensor to pin 85 of relay
from pin 85 to diode to compressor connection
Should radiators be grounded?
- Thread starter dang
- Start date
absolutely!
we actually run 40 amp fans so hot through sensor is no good!
to be clear— at shop we run green wire from coil to fuse to sensor.
from sensor to pin 85 of relay
from pin 85 to diode to compressor connection
Agreed. I already have the relay wired and mounted and only need to add the temp switch in the circuit. I'll end up with a setup like Ohmess is describing.
Thanks for the link to the switch Don, that will finish up my project nicely.
I'd also wire it so that the fan will run when the switch is calling for it to run, even when the ignition is off.
That’s the function of a turbo timer- run if warm for limited time after key off.
Stock part on the BMW 745i 40 years ago.
Stock part on the BMW 745i 40 years ago.
I would agree if the temp switch is set for a higher temp. If it's a 180deg or so I think shutting off with ignition is no different than having a fan on the motor stop.
Honolulu
Well-Known Member
seems to me I read somewhere, decades ago, that one could test your coolant by putting one probe of a multimeter (set to DC volts) in the coolant, the other on a ground. The voltage measured would inform how "good" the coolant was at preventing electrolysis. But that was then, and this is now, that's all I got.
Grounding through the coolant is a bad idea for the corrosion reason when currents go through it. I read that a sacrificial anode floating from the radiator cap helps avoid corrosion. Honolulu is right that measuring voltage is a way of knowing if there is a problem. More than 0.3V is bad, more than 1V and you have a battery you can use 
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Whether to wire this way is a tough call. If you think you will have frequent short stops, where the continued cooling will be useful when you restart, this may make sense.
In situations where the car will sit long enough to cool the coolant below 80 degreesC before you run it again, this is a waste of energy.
So it depends on how you expect to use your car.
To me for these cars, wiring it so the fan stays on is a dead battery waiting to happen.