How to Remove a 1994 Toyota Pick-up Heater Core

by Walt Sampson
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The heater core on a 1994 Toyota pick-up may need to be removed if it is leaking or its air passages have become clogged by debris coming from the air flowing through it. The heater core is located in the heater unit assembly that is located under the dashboard next to the glove compartment. You have to take out both the glove compartment and the heater unit assembly to remove the heater core.

Step 1

Open the hood and disconnect the negative battery cable with pliers. Make sure the engine has cooled down. Place a drain pan under the radiator. Remove the radiator cap by hand. Open the drain valve on the bottom of the radiator with pliers. Drain the coolant from the radiator.

Step 2

Open the passenger-side door. Detach the Phillips screws that hold the glove compartment in place. Remove the glove compartment from the vehicle. Use a flashlight to locate the defroster hoses, which extend up from either side of the heater unit assembly. Pull them straight up by hand to disconnect them. Remove the side defroster ducts, using pliers to take off the clamps. Detach the air damper assembly to the right of the heater unit by removing the screws. Pull the air duct free of the air damper assembly and the heater unit.

Step 3

Pull off the heater control knobs by hand. If your truck has air conditioning, pry off the air conditioner switch with a flat-head screwdriver. Pry off the heater control plate using a flat-head screwdriver. Remove the Phillips screws securing the heating control assembly and pull out the assembly by hand. Unplug the connectors by pulling them apart. Remove the assembly from the truck.

Step 4

Detach the hose clamps on the two heater hoses in the engine compartment, using a flat-head screwdriver. The hoses are on the upper part of the firewall on the passenger's side of the engine. Pull off the hoses by hand.

Step 5

Remove the three retaining bolts holding the heater unit assembly, using a socket wrench. The heater unit is under the dashboard on the passenger's side. Remove the heater unit assembly from the vehicle.

Step 6

Place the heater unit assembly where it is supported and you can work on it. Remove the clamps holding the two pipes that go to the heater core, using a screwdriver. Remove the set screw with an Allen wrench. Unfasten by hand the six clamps that hold the two halves of the heater unit together and separate the halves. Carefully pull the heater core out of the heating unit.

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