i have been using this harness since he started building them...had 1 relay go out on me and replaced them all at 1 time...been good since

 

I've had the Nelson harness for about 5 years now, and it didn't give me any problems until my truck sat for 18 months and I got it running again and two relays pooped out. The harness performed flawlessly before the trans blew on the truck and it was sleeping for a while. I put some new relays in and it's been great ever since. I'm very happy with it and would get another one if I had another truck

 

mines running strong after a couple of yrs of use.. hell i thought my relay went out this wk, but it looks like 1 of my fan motors kicked the bucket b4 the harness

 

i got a nelson an it burn then i got a black bear an it burn also,, btw i have oem 2005 fans looks like this only happens with this fans

 

could be, but, the heat comes from the amps. When voltage goes down, amps go up. Load is what causes amps to climb. Load can come from a shorted motor, and loose connector, to small of a wire gauge, dirty contact, or to much load for a certain circuit. Might want to check the other possible causes before condemning the wire size....

 

If the Fan motors are getting weak or burning out, they will draw more current.
The easy way is to find a local electric motor repair shop and ask them to do a quick load test on the motor. If it's pulling more amperage than it should, you found your culprit.

I would not run a larger amperage relay due to the fire hazard. Double and triple check your contact points. Make sure your pins are tight and clean.

I had to build an extention on my Nelson harness just because of where I mounted it. They are standard crimp spade terminals you can remove from the interlocking relay pigtails. If you need to replace one because it's burnt out, MCM and Mouser sells them.
That would be my only complaint so far - too short for the blue PCM wire. Little longer and I think it would be perfect. I mounted mine to the Fan housing and away from the PCM cover, so it removes as a unit.

I wish I could find the interlocking relay sockets. All Electronics had them many moons ago, but have not been able to find them.
I would replace the sockets, pop in the connectors and fresh relays providing your wires aren't melted.
Re-check your grounds. A bad ground will make the fans Hunt for a new one and possibly burn up the PCM.
( I see this all the time with auto amplifiers with poor grounds)

 

I picked some up from Waytek when I built my harness.
Item # 75280