Ive been using optitronic 30A relays from advanced auto for about 6? Years now. Never had a issue. They were only $4 too.

Im not sure how they set the tunes. But i have mine when the fans do come on they stay on for as lang as possible after the target ECT is met. That way the relay isnt constantly gettin switched.
Also ran 10ga hi-temp wire and grounded really good.

If yall need some help making a harness lemme know.

 

if their both never coming on then they forgot to turn on the settings for the pcm pin, or your ect is never reaching the trigger point they set in the tune. You have an aftermarket stat? I know I tapped the right green wire, mine come on like they are supposed to when the compressor clutch engages. I am using borg warner relays. I noticed the plastic around the relay for the pcm pin is melted a little where it plugs in, and the relays that blow sometimes have white around the terminal like they got hot. I'm probably going to start by increasing the size of the ground wires for the harness, but really have no idea if that will solve the problem.

 

You're burning relays at the coil terminals (86 or 85)? That's seriously wrong. That sounds like some kind of back feed problem that needs a diode to resolve.

 

Had the same harness for a while and never had a problem. Like the other guys said check out the relays.

 

the only thing wrong with the relays is that their blowing... I know something is wrong. Everything is hooked up correct though, power is coming from the red distribution block and the ground is hooked up to the alternator bracket I believe, however nelson recommends to hook it up. The relay thats giving the most trouble is the one on the end closest to the fans, seems to control the ect pin 42. Expound on a diode and why I would need it?

 

If indeed your burning relays are caused by a back feed through a coil terminal, a diode in that terminal's wire will keep the electricity from flowing in the wrong direction.