hot in 86.

[GreenHornet71]

Relays and temp sensor changed still no fan. What next? Fan works when powered

 

[RmvBfrFlght]

Try this, locate the fan switch that is mounted in the intake manifold. Will have a GRN/YEL wire going to it. Disconnect the connector from the switch and get a piece of wire to run from the connector terminal to the engine (to ground that wire).

Key-on, engine-off, use the wire to connect the GRN/YEL wire terminal to the engine someplace. This should run the fan in high speed mode. If it doesn't, does the relay at least click? If so then the fusible link at the starter is likely bad.

If the relay isn't clicking then check the RLYS fuse in the fuse block (top of block).

If that fuse is OK then there is a wiring issue such as a cut or broken wire.

RemoveBeforeFlight

 

[GreenHornet71]

Try this, locate the fan switch that is mounted in the intake manifold. Will have a GRN/YEL wire going to it. Disconnect the connector from the switch and get a piece of wire to run from the connector terminal to the engine (to ground that wire).

Key-on, engine-off, use the wire to connect the GRN/YEL wire terminal to the engine someplace. This should run the fan in high speed mode. If it doesn't, does the relay at least click? If so then the fusible link at the starter is likely bad.

If the relay isn't clicking then check the RLYS fuse in the fuse block (top of block).

If that fuse is OK then there is a wiring issue such as a cut or broken wire.

RemoveBeforeFlight

Ceramic block behind fan seems to have overheated visible heat stress on block and positive wires. What is this?

 

[RmvBfrFlght]

It is a resistor that is used to run the fan at a lower speed. The low speed of the fan is ECM and A/C pressure switch controlled. If the resistor is open the fan won't run at low speed. It should still run at the higher speed via the intake manifold temperature switch or the A/C pressure switch.

A lot of folks bypass the resistor by running a wire from terminal to terminal on it. This has the fan running at high speed any time the fan is requested.

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