My old truck (fuel injected '92 Ford Ranger) has 2 temp sensors, located where the hot coolant leaves the engine.

  • One sensor goes to the ECU, which alters the amount of fuel which is delivered to the engine depending on the engine temperature.
  • The other sensor goes to the analog temp dial on the dashboard. The temperature dial has arbitrary low/med/high levels, so it is not very helpful if I want to know exactly how hot the coolant is when it leaves the engine.

I installed a digital temperature gauge in the cabin. I cut the wire leading to the dial gauge on the dashboard and connected it to the new digital gauge. The digital gauge now displays the temperature of the hot coolant.

This is where the question shifts over in the electrical realm.

I want to have both the old dial gauge AND the digital gauge running at the same time. But when I spliced the wire coming from the temp sensor and connected one wire to the dial gauge, and the other wire to the digital gauge, neither gauge displayed the correct temp.

It looks as if both the dial and digital gauge are displaying half the correct temperature. Eg: if the engine was running hot at 300 degrees, the dial would display medium, and the digital would display 150. They should be displaying hot and 300, respectively.

If I understand how the temperature sensor works, the resistance changes depending on how hot the sensor gets. Correct? In my case, this current is getting split to 2 separate gauges instead of one gauge.

So if I want to direct the current to 2 separate temperature gauges, I would need to double the volts/amps coming from the sensor, correct? Is there an easy way to do this? Is there a way to "do" the opposite of resisting a current?


  • \$\begingroup\$ Do you have the reference of the gauge? \$\endgroup\$ – David May 15 '18 at 22:08
  • \$\begingroup\$ Possibly. I will need to check storage this weekend... \$\endgroup\$ – Sam May 15 '18 at 22:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.