Hey there, i really could use some help on this one. My Radiator fan still will not turn on, let me explain what i have done so far, i have replaced and fixed the wiring for the relay, it wwas destroyed, and replaced the relay still nothing i have checked the relay and it works fine when i manually close the relay, the fan turns on just fine, i have checked the coolant temp sensor, i measured resistance on it and the resistance varied with the hotter water that i put into it, so i think that is good, i have a v6 2.8L MPFI i am at a loss now i need to know what else is in this circuit that would make the relay not open and close on its own, could it be the ecm, and is there a way to check it? i am at my wits end with this problem can someone plese help?

 

By destroyed, do you mean it was torn out of the car ?

If so, it my not be tied to the ECM anymore (or, fan switch). The ECM ground wire is a dk green/ white wire. Make sure is is a complete circuit to the ECM.
Make sure the 'C/H FAN" fuse (20A) under the dash isn't blown as well.
Removing the fan switch wire and grounding it with the ign on should make the fan run as well.
If none of those work, you've eleminated some of the possibilities and work from there.

 

check the inline fuse by the bat.

 

That would be the fuse for the ECM and fuel pump power (which is generally true for all years that have that fuse). The fan(s) are powered direct and are on a fusible link.

 

ya, but theres two in-line fuses, one for ecm, the other for the fan. pretty sure. Im checking out the diagrams for a 2.8L engine cooling fan system (page 10-31 in the Haynes manual) from the relay, theres a fuse in the fuseblock (10amp), and another inline fuse (20 GA-RUST) its the red wire thats has power going to it all times. so in all Two fuses for the fan relay. Grosskhr, try turning on the a/c, if the fans arnt running with a/c on, then its a relay issue/power

 

I'm going by the '87 Helms service manual.

The relay coil is powered by the 20A C/H fan fuse (switched ignition). The relay switched constant power, from the battery, is direct wired to power via a fusible link. There are no other fuses (shown) for the fan circuit.

It is the same for '87 vin 8, F and H.

The only other in line 20A fuse shown for power distribution, is for the MAF for v6 only. The other 20A inline powers the fuel pump and the ECM (the one by the battery). On the TPI, the MAF and burnoff relay were on the FP/ECM inline 20A fuse.