I would like to install a led light that lights when the tc is locked. With this light I could better tell if I would need a mystery switch. How would one wire a led light for this purpose without installing the mystery switch?

I tow a heavy 12k fifth wheel. Sometimes while using cruise control and climbing hills the trans will downshift to maintain speed. With the mystery switch in the on position will the trans still down shift or will the trans stay in the same gear?

When going down hill and my speed drops below 50 mph I will down shift to second manually and then press tow haul in an effort to use engine braking. Of coures I want the tc to lock to help slow. A led light would help me make a decision if I should install the MS.


thanks for your help

 

I sure wish someone knew how to wire a light to tell if the TC was locked.

anything guys.

 

I have one on my truck. It works great. I did the lock up mod and added an led in the circuit. I have the wire that is tapped into the lockup circuit go to the toggle switch, then the other side of the switch goes to ground. On the side going to the lockup circuit I added a wire for the LED then ran the second wire from the LED to 12volt. When the converter locks up the LED lights up. When I flip the switch to on the converter locks and the LED lights.

 

The TC solenoid is on a switched ground circuit, so applying voltage to one side of the LED and allowing the grounding of the solenoid to complete the new circuit should work fine.