I'm somewhat confused about my fans on a 94 Z28.
The car has been throwing a check engine light and as a default the car kicks on a fan(there are 2 but only 1 comes on).
Now that I cleared up the check engine light the car warms up to the middle of the gauge(normal temp?) before engaging the fan. The temperature never seems to go back down and slowly climbs higher while idling. By comparison with the check engine light on the fan would keep the engine from ever getting above the 1/4 mark above 160.

My question is why does it seem to cool differently and why does it feel like my fan is blowing out the front of the car rather than pulling air through the radiator. Hand behind the fan feels no circulation, hand in front of the radiator gets air blown on it. I know someone has messed w/ the wiring but are their 2 separate circuits controling the fan that 1 would be correct and the other reversed(in reference to the SES vs. temp switch activated)? My understanding is that there are only 2 relays on this system, 1 for each fan.

My AC compressor switch is bad so I can't get the aux. fan to come on. I'm considering wiring them together but concerned about the draw on the system by running them all the time.

I did not get a chance to run it w/ my cable hooked up to see exact temps but the gauge approached the 3/4 hot mark. I've purged the system correctly, it has water and water wetter in the system. I will try to jumper the pins to see if both fans are even operational in the morning, but currently i'm needing some fresh ideas on what else to check.

 

1994s could have a 2 or 3 relay system. It depends on when it was built.
If you have a 2 relay system, you have primary and secondary fans. The LH or primary fan comes on at the first ON temp threshold (226°) set in the PCM. The RH or secondary fan comes on at 235°.

I am not positive, but it is possible that if the primary fan leads were backwards at the fan, then it would run in reverse. It would depend on the motor windings. It definitely should not blow toward the front.

For sake of argument, let's say it does. With the fans working normally and no SES, the primary fan would be fighting against air coming into the front of the car. Probably not adequate for cooling.

When you had the SES on, BOTH fans were running. If the secondary fan is wired correctly, it would pull air in as it should and not fight incoming air. That may be why your temps were lower at that time.

When you get around to it, shorting your DLC pins should tell you if there is a difference in operation of the two.

 

Thanks for the help. I had actually referenced your page about 1/2 way through working on the car. its loads of help.

I am able to get both fans to come on w/ the jumper and w/ both fans going i'm getting positive air flow, i can remove the jumper and watch the fans slow down and see they are both spinning the same direction. I'm installing a real temp gauge in the morning to see if my sensors are functioning properly because the car just seems to get hotter and hotter even w/ only 1 fan running. I've got a data logger but can't find my dang cord to check what the PCM is seeing.
Can I wire in both fans together to aid in cooling(i know I physically can but are their draw backs to doing this) or is the best way to do it through programming them to come on closer to each other?

 

Obviously, the best way would be programming, but you could also install a fan switch. You could also bridge the fan relay control wires (dark green and dark blue) together so it would trigger both relays at once, but it might cause a DTC 77. Bridging the load side of the relay power to both fans would not be a good idea, because you would have the load of both fans running through one relay.