I just finished up my ls swap. I am overheating every time I drive it. I notice that the first fan comes on and runs at 190. After a little bit of drive the second fan tries to come on at 210 and blows the 20 amp fuse which shuts off the first fan and I overheat. Any ideas? Bad fan drawing to many amps? Need a bigger fuse? Any help would be great. Thanks.

 

What fans are you running? Factory dual style TPI? LS style using the factory harness? Aftermarket?

Never ever just throw a bigger fuse at it. A blown fuse is protecting your circuit. Need to find out what's causing the excess power draw. Bad ground, bad relay, wire shorting to ground...something along those lines.

 

Dual tpi fans. From my understanding both fans work off the same ground. I have one fan that works. I am thinking the second fan motor is the problem causing the excessive amp draw.

 

2nd fan should come on around 230ish or when the AC is turned on.
Is your cooling system clean and flushed, good thermostat, pump..ect?

 

I would start checking relay, the wires surrounding it. It could be that someone tried to rig a switch for it to turn it on manually.

 

This is an Ls swap. The computer is setup to turn the second fan on at 210. Brand new water pump, thermostat, and coolant system flush.

 

oh...

 

After doing some continuity checks the motors are good. There is not any shorts to grounds. The relays are good. Only thing left is drawing to many amp to keep one running and starting another. Sounds right?

 

So do you have your LS ecm triggering 2 separate stock 3rd gen relays then?

 

run separate power wires for each fan, with a fuse in each power wire. this will split the load to 2 different circuits instead of just one.

 

Is your wiring from an LS car or is it 3rd gen?