my harness did the same thing with the relays provided, however, it has been fine since I swapped all 3.

 

What did you swap them to?

 

What are your settings? What stat are you running? What kind of fans?

 

My truck sits at 185 while in town and moving, AC on with LS1 fans. It'll go up to 190-195 if I'm stuck in traffic. I have them kick on pretty early though. I think they kick on at like 170 or something, I'll have to look. You can get 60 amp automotive relays, but I doubt the amperage has anything to do with it. I would think a 40amp relay would be sufficient.

 

It could be the fans that you're using!!! I have a Flex-a-lite set and my temps on 90*+ days, stays right around 175-183 on my Efi scanner!! With the AC on full blast, it gets to 190!! I haven't even seen 200 since I've installed these things with the nelson harness!! I have an extra Flex-A-Lite housing if you want to try it out. As for the fans well lets just say they weren't hooked up right when I first installed them and I blew the motor...but they might give you a decent price on the fans if you swap my bad ones for some new ones. IDK if it's worth it for you though.

I can say this...I have put my stock fan back on before when those two fans went out that I mentioned above. It kept my temps at 210 the entire time!!!! it never got lower once it got there. It did, however, reach it's highest that I've logged before and that was 218!! This was on a slightly colder set of days and with no AC running!!

 

Well I towed the boat to the lake today. It was 115* in town, and on the uphill drive to the lake my EFILive scan tool showed ECT's as high as 248* I ended up driving part of the trip with the heater on full, slightly uncomfortable. Average for the trip up and back was probably in the upper 220's low 230's. Either e-fans suck for towing and in the heat, as I have heard before, or there is something wrong with my radiator or water pump. I bought a clutch fan and shroud today, should be in next week and I'll find out for sure if the e-fans are the culprit.

I generally only have an issue when the outside temps go over 100 or so. If it is 90* out and I run the a/c, my ECT's never get over 200, generally stay in the upper 180's low 190's.

 

I think it is just your settings, not the fans. Could be wrong. Maybe they weren't hooked up right? I have the FAL fans also and a Nelson harness. One of my fans stays on 100% at 100% power. The other one kicks on when a certain temp is reached or I turn the A/C on. Towing with my boat (under 3000lbs) in 95* temp in around town traffic I have only seen temps close to 190* - about 187*. If I turn the A/C on, which I only do occassionally, I can get to 190* - but that is as high as it goes. The FAL fans pull over 5000cfm. Once I get on the highway I generally get temps in the 183* range, using a scan gauge. It doesn't matter about the A/C then.

What are your fan settings?

 

PCM triggers both fans on low based on temp. Right now my tune says fans on at 189 and off at 180.

A/C triggers one fan on high

Both triggers at the same time turn both fans on high

I don't know how much air the OEM fans pull, but this is the same set of fans that comes stock on the newer trucks, so I can't imagine it's not enough.

 

my fans and relays seem to be working just fine with my "white1" harness
my fans turn on and off the same way yours do, but I have a stock stat so of course my temp settings are different.

1BADC10 did a 5.3L swap into his '86 C10, he can't seem to get the temps below 200* even with a 180* stat, even cruising on the highway where my stock stat will get me down to ~190* in hot weather

 

do u have a lower tstat?