Hello, All!
1987 IrocZ with 5.7 TPI. I have tested entire cooling system, and am down to what actually controls the grounding for fan solenoid... When I jump A & B in ALDL the fan will turn. When up to temp, no ground to fan solenoid. I have swapped computer, but not the prom or "chip". Could it be that? Getting a little frustrated, and could use your experience and help! Thanks for responding!

 

Any codes 15 ?
Fan solenoid do you mean the fan relay ?

 

Fan switch in the block is the ground for the relay

 

Fan turn on temp is 16 billion degrees Fahrenheit, are you letting it get hot enough for the fan to kick on? Actually it's only 230* +/-. With the airdam and a 180* thermostat, about the only time the fans on my thirdgens ever kicked in, was after relatively hard driving, in hot weather, and then suddenly being stopped, like in a drive-thru or bumper to bumper traffic jam on the interstate in a busy city.

 

The cooling fan was working properly, then inop. From what I understand the computer needs forward speed less than 40 mph and temperature signal to turn fan on. I could wire in manual switch, but want to keep it clean. Any more thoughts????? Thanks for responding!