Since current is increased and voltage remains the same, mathematically resistance must decrease.

Correct.

 

Its works! I put a 10k resistor (because that's what I had lying around) in parallel. Just stuck the leads inside the back of the connector. Definite improvement when the fan comes on. I don't have exact temps but, I was sitting in a long fast food drive through line and the fan came on and shut off several times. By looking at the panel gauge, I'd say it's pretty close to 210F.
Thank you all for taking the time to help with this!

 

Good to know it does what you want now.

 

Its works! I put a 10k resistor (because that's what I had lying around) in parallel. Just stuck the leads inside the back of the connector. Definite improvement when the fan comes on. I don't have exact temps but, I was sitting in a long fast food drive through line and the fan came on and shut off several times. By looking at the panel gauge, I'd say it's pretty close to 210F.
Thank you all for taking the time to help with this!

hi Eover,
I’m trying the exact same thing, I have a Rover 1.8 and the fans come on at 105 degrees C, I’d like to use a potentiometer to lower the resistance to get them to come on at 93 or 94 degrees C.

Can you please advise how you wired your potentiometer?

I wired in a 10K POT and this is how I wired it - Left wire is just a ground to a good engine chassis point. Middle is the signal from the coolant temp sensor, i spliced from the wire between coolant temp sensor and ECU, and the right hand wire is simple going from the POT and rejoins the wire that goes from sensor to ECU. The coolant temp sensor has 2 wires, one being a ground wire, the being a supply from the ECU, about 5V.

What this allows is for the resistances to be increased, meaning the temperature is lower than what it actually is, which doesn’t help me and I need to lower the resistance.
when you say you wired yours in parallel, can you kindly adv which wire you connected to which port of your potentiometer.

 

When I had a thermostat issue I used an old NASCAR racer trick: I drilled a 3/16 hole in the control thermostat plate. The engines warmed up faster and held the required temperature without quite a s much fan running.