1991 Ford Bronco water temperature sending unit

For the location of your unit, see the accompanying illustrations.

Disconnect the negative battery cable.
Drain the cooling system into a suitable container.
CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.
Disengage the electrical connector at the temperature sender/switch.
Remove the temperature sender/switch.
To install:
Apply pipe sealant or Teflon  tape to the threads of the new sender/switch.
Install the temperature sender/switch and connect the electrical connector.
Connect the negative battery cable. Fill the cooling system.
Run the engine and check for leaks.