98TAauto

iTrader: (2)

guys, is there a way to make sure the low speed fan is getting power. Its the ls1 fans and the nelson harness. Both come on high speed with the AC on and or defrost also. But today at the drive in my temps went well over past 210... normally they are 210-205ish at operating. Its never been that high and I couldnt get out to check to see if the low speed fan was on. But driving daily i havent seen it come on, but temps are cool so im sure driving it keeps them around 210

but both come on high when i have the ac on.. something just doesnt seem right with the fans and I dont want someone else driving my truck and overheating it cause the low speed wont engage. The pins in and its nelson tuned for them. I think i have 4 pin relays but they are for 5 pins.. would that make any difference?

Other than sitting and waiting 3 hours for it to overheat is their a way to make sure certain wires have power? Hotwired the low speed worked fine

bluecajun5.3

iTrader: (31)

i have the same problem as you. i just manually turn them on with a togle switch to make them run both on low. ac compressor kicks on, they both turn on high. i parked the truck running and got around 215 and they still didn't kick on.

negativeswitches

iTrader: (15)

i dunno how nelsons harnes works or anything but i wired my ls1 fans on a generic thermostat works perfectally, and mine are single speed dual fans no high and low

hope this helps,
-Erik

budhayes3

iTrader: (19)

Something sounds a little off...did you try manually grounding the pcm wire? With the a/c on, only 1 fan should come on high unless the pcm wire is grounded, in which case both come on high. You could try swapping some different relays in for a quick check...maybe it does need 5 pin relays?