From what I've seen they basically are the same and the same price but is one better than the other? Any difference in fitment? I am going to be using 05+ 34 inch fans and want as clean of an install as possible. Does the harness have clips on it to pop into the holes in the shroud so the wires are all nice and neat running across the shroud and do the relays mount somewhere out of the way or just taped inline with the harness somehow? Are the power and ground leads long enough to run up to the positive cable junction block?

 

Kurt, I know ive shown you this before, but make your own

 

Whats the deal with the 3 relays? Does it have to do with low/high speed. I've never had to worry about it as my truck came with it, but I am curious to learn how that works.

 

I went with a BlackBear harness and put in a manual override switch.

 

some people had issues with the relays nelson was using with their harnesses. i believe they started using upgraded relays since then. my nelson harness is almost five years old and ive never had a problem with it running my larger 34" efans... the three relays are mounted together. the best place for them is on the ecm cover. the wires are long enough to go to all needed connections and look like a factory install

 

I really like the Black Bear harness and it works well, but I do have one problem with it. All 3 relay plugs have melted pretty bad. Ill post pics when I get home. I thought I had them online, but I dont.

 

I know how the fan circuits work and I could make my own but I figure a minimum of 40 bucks for both fan connectors, plus 5-10 bucks for a roll of 12 gauge wire, plus 8-10 bucks for heat shrink style but connectors the good ones that are safe to use on air bag systems, yea those, then good heavy duty relays and then trying to find a nice 3 relay holder setup, its just not worth it. At best I would break even and have more time involved.

I've read about the older Nelson harness relay problems which is why I'm curious about the Black Bear harness.

Personally I think a lot of the melting issues are because of the fans being worked too much. Back when I had a single fan on my 95 and no PCM control it was wired so when the AC was on the fan was always on. It worked but eventually the wires melted to the motor. The settings I'm going to use on my 99 will run the fans only when needed and otherwise be shut off.

 

I have the factory settings as I still Have the Stock t-stat. The fans have to run when the AC is on or the system will build too much pressure and pop the safety valve. I learned this the hard way.

 

Ive had the nelson harness for a couple of months or so, relays took a **** fast. Upgraded relays and haven't had a problem since.

 

I have about $40 in my harness and its been fine for 3 years with ls1, and 05+ fans. You can probably pull the pigtails with the fans if you go to a scrap yard, I jut picked up some fans with pigtails for $50 last week, but if you cant, the connectors are $15 off ebay.

For the guy that asked, when the fans are on "low" the circuit is designed to run in series so the fans only see 6v, ie, half speed. When the high command is triggered the relay is tripped and the fans are now in parallel and see the full 12v. This is how gm does it for the factory fans, and its pretty clever.