How to install E-Fans

[bottomline2000]

You'd be amazed how well our trucks run without any fans. The big radiators are very efficient so cooloing shouldn't be an issue either way. Its hard to get the truck up to temp if everything is in good working order.

I went back and checked my order. It was actually from amazon and I have the 53's. They are the higher 7 blade count model for the newer trucks. Hope that helps.

 

[YukonXL04]

Pretty sure I have the 620653 in mine. Haven't had a single issues in 100+ Temps towing or idling while keeping the truck cold. Very happy with mine

 

[DPGDirk]

Good to know. I think I'll shoot for the 620653 and see what happens.

Both Dorman models have twin 7 blade fans. The factory models had a 5 and 7 blade combo or a 7 and 9 blade combo.
They're just spinning the 7 blade fans faster in the 620654...

 

[DPGDirk]

Almost done. This danged thing has fought me every inch of the way. Doing multiple other upgrades simultaneously though.

Gotta take the new belt back and get the larger one for these models.

Mounted the stinkin' relays to the PCM cover 4 different times! Fans were hitting them, so they had to come out and be moved. Mounted them upside down once.
Probably shouldn't be working that late...

 

[DPGDirk]

Done!

Does the AC clutch engagement trigger the fan on '03 and newer models or just through '02? Mine seem to be working fine, but don't come on with AC.

A few points. The instructions from LS1fans.com are not great. That's putting it mildly. There is a green ground wire in their harness that should be longer. It said "Driver side Rad mount" on one side and "Neg 12v ground" on the other. It was wrapped around a wire at the passenger side fan plug. Nothing in their instructions about this wire. Multiple other little details that are missing or not clear.

You'll probably break the plastic plug covers that cover the PCM plugs, as the OP did. They suck! Some complained how hard it was to push the pins into the PCM plugs. I found that to be the easy part- once I finally accessed that thing to start with! I pushed mine down in there with needle nose pliers and finished with a bent paper clip. Slipped right in.

The Dorman 620653 fans seem really nice. Very well made. Perfect fit and quiet. There is a difference in throttle response- not huge, but it's there. looking forward to better working AC next summer!

 

[YukonXL04]

Yes the AC will trigger the fans to come on. I believe you still have to be up to a certain temperature though. I remember thinking mine weren't working, but it wasn't getting hot enough just idling... I had to drive it around some and then they kicked on. Its hard to tell because you cant really hear them. Mine are really quiet, you only hear them if they are on high. I dont remember having any problems with the harness, it would have been nice if they had added an extra 12" of wiring though.

Im also running their alternator overdrive pulley too.

 

[bottomline2000]

Done!

Does the AC clutch engagement trigger the fan on '03 and newer models or just through '02? Mine seem to be working fine, but don't come on with AC.

A few points. The instructions from LS1fans.com are not great. That's putting it mildly. There is a green ground wire in their harness that should be longer. It said "Driver side Rad mount" on one side and "Neg 12v ground" on the other. It was wrapped around a wire at the passenger side fan plug. Nothing in their instructions about this wire. Multiple other little details that are missing or not clear.

You'll probably break the plastic plug covers that cover the PCM plugs, as the OP did. They suck! Some complained how hard it was to push the pins into the PCM plugs. I found that to be the easy part- once I finally accessed that thing to start with! I pushed mine down in there with needle nose pliers and finished with a bent paper clip. Slipped right in.

The Dorman 620653 fans seem really nice. Very well made. Perfect fit and quiet. There is a difference in throttle response- not huge, but it's there. looking forward to better working AC next summer!

If you have an 03 or newer truck your fan will be triggered by ac pressure not the ac clutch. It all depends if you have the 2 wire setup to the pcm or not.

These big radiators are pretty efficient and it takes a while to get them up to temp to trigger the 2 fans on low from coolant temp.

I just saw a suburban come thru my neighborhood yesterday with its clutch fan blaring. I hate that sound and the drag it puts on the engine. Like driving around with a parachute. It was cold here yesterday and makes me wonder if their clutch fan was broke lol. The difference in efans and your clutch fan would be very noticeable during the summer and your ac should be ice cold! Glad those Dorman fans worked out for ya.

 

[DPGDirk]

Thanks!
The LS1 Fans instructions said the fan should kick on when the AC clutch engages. It doesn't say anything about different years. I'm thinking the models prior to '03 were triggered differently.

 

[bottomline2000]

Thanks!
The LS1 Fans instructions said the fan should kick on when the AC clutch engages. It doesn't say anything about different years. I'm thinking the models prior to '03 were triggered differently.

Fans on 00-02 models work off the ac clutch. Typically when the ac clutch engages the passenger side fan cycles high. If you tapped the ac wire then this is how your fans will trigger. The coolant trigger is still there and seperate.

 

[DPGDirk]

Fans on 00-02 models work off the ac clutch. Typically when the ac clutch engages the passenger side fan cycles high. If you tapped the ac wire then this is how your fans will trigger. The coolant trigger is still there and seperate.

I'm running the LS1 Fans harness. It doesn't have you tap into an AC wire on an '03. Just plug the 2 pins into the PCM plugs, hot wires to the battery red box, plug in 2 fans and a ground to the radiator support.

It did say that the fan should kick on when the clutch engages though, which is what had me puzzled.