I have a 1987 Formula 305TPI. 112K. I have been chasing my cooling issue for months now. Whenever I drive the car it heats up at the normal rate, but it will go all the way to the red area of the gauge at 260 and the fan doesn't turn on. To stop it from doing that I have to run the heater all the time. When it's 90 out, things stick to places that they shouldn't. I have pulled the fan and applied 12v to it and it spins like it would if it were working in the car. I replaced the fan switch and the relay with no luck. The rad hoses, thermostat, and water pump are all new within the past 2 months. So, I pulled the connector from the fan and the relay and tested the wiring. Less than 2 ohms on each. Damn! Now what? So, I carefully disassembled the relay connector to make sure that none of the crimps had failed. Nope, all fine. The only thing I can think of now is that the relay connector is wired wrong.

Here is how it is now as my car sits disassembled in my garage.

A: Black w/red stripe

B: Yellow w/white stripe (2x)

C: Green w/white stripe

D: nothing

E: Orange

The pattern matches the terminal pattern of the relay.
Maybe I put it together wrong, Maybe it was wrong before that, I don't know.
Please help.
I'm gonna go kill something now.

 

This is how is should have been wired once:

 

Disconnect the fan relay connetor and grab your voltmeter. Reference the black lead/probe to a good ground.

There should be a constant +12VDC on the E terminal (orange wire), regardless of the ignition switch position. If not, check the fusible link and battery connetions.

There should be +12VDC on the C terminal whenever the ignition is turned on. If not, check the fuse panel, wiring, and ignition switch.

Turn off the ignition and switch to a resistance scale. There should be relatively low resistance to ground on the A terminal, since you would be reading through the fan motor armature. A few ohms is about right. Anything over 10 ohms indicates a continuity (wiring) problem.

There should be relatively high resistance on the B terminal to ground, but be careful not to test this unless you have a low-current ohmmeter. If you have an old analog ohmmeter, skip this test so you don't risk damaging the ECMs output transistors. Test on diode check range or over 2K ohm scale.

If all voltages are correct, and the fan is intact, reconnect the relay. Insert a jumper wire in the B terminal of the relay socket. Turn on the ignition, then briefly ground the jumper wire you inserted. This should compelte the ground circuit for the relay operating coil and turn the fan on.

If you hear/feel the relay click, but have no fan operation, there is a problem with the relay contacts, fan power wiring, or relay socket connection. If the voltage at the orange wire drops significantly when you ground the relay coil, the problem is likely with the fusible link or power circuit that supplies the relay. If the orange wire maintains voltage, but the black/red wire gets no voltage, the problem is either the relay contacts or socket connections.

If you do not hear/feel the relay click, you have either a faulty relay or probelm with power to the C terminal.

 

I found the problem. The fuseable link was melted.