Installing a Torque Converter lock up switch on a Ford Ranger.

The lock up TC circuit is a ground switching system. The ECU grounds the circuit to control the operation of the TC. So in order to install a switch to force lockup all you have to do is hook up a grounding circuit.

Locate pin #53 on the ECU. They are numbered on the ECU.

Tapp into the pin #53 wire in the engine management harness.

Run a wire from the pin #53 wire to a switch, then from the other side of the switch to a good ground. I ran mine to the negative battery terminal.

Note: Haynes manual says the wire is Pink and Yellow but mine is Orange. You can verify the wire color by looking at the TC plug on the transmission.

Now you can control lock up. When the switch is in the on position the lock will stay locked up regardless of engine load as long as the transmission is in 3rd or OD.

When the switch is in the off position the lock up will operated as it always did.

Note: There is no lock up in first or second. The valve body overrides it in those ranges. Also remember to turn the switch off when coming to a stop or the engine will lug down until the transmission drops out of 3rd gear.

Benefits:

You can force the TC to stay locked in 3rd and OD. When you take your foot off the gas in 3rd or OD the TC unlocks and then relocks once the gas pedal is pushed down. IMO this causes un necessary wear and heat. With this switch set up once turned on the TC will not unlock until you either turn it off or shift into 2nd gear.