Option for fan harnesses

[farmtruc]

Hey guys, I've built both types and wanted your information/feedback on this.

There are two ways I can go on this fan harness. Here are the two options. I'm only going to build one of them so which one do you think is better.

Fan Option 1: The setup includes three relays and the ls1 fans or flex fans. Fan 1 will turn on full blast when the PCM detects a predetermined setting (180deg). Fan 2 will turn on when the A/C is turned on. If the engine heats up and the a/c is on, then both fans are on. This option has kept my father in laws truck very cool for the last couple of weeks with just one fan one. When the a/c is on, the engine still stays cool and the a/c still blows cool.

Fan Option 2: When the engine reaches a predetermined temp, the fans will come on low, the fans will be in series. When the a/c is turned on, the fans will come on high, parallel. This option has also kept my brother in laws truck very cool.

Either way is going to work, with option 1 , the engine runs cooler than with the stock fan clutch and that is only with one fan running, the other option, no problems either.

Since fan option 1 is turning one fan on high right away, there was a very small , i mean small drop in voltage for just a sec, then it came back up. It only dropped one tiny mark on the gauge. This was at night, with the radio on, high beams and a/c.

I'm leaning towards the first option, this is just a preference thing.

What do you think?

thanks for the input,

allen

[ONE04FX4]

send me option two.

[MacADaYear]

Option 2 sounds good but....

Lets say its a really hot day and you have your fans kick on low and your temps still rise. If there was a way to get them to go full speed besides using the a/c that would be perfect.

[Stall Speed]

I like opyion 2 since more surface area of radiator is being cooled.Also have an optional manual on switch for high cooling when desired.

[02P3wZ71]

I personally like option 1. That's my order please, can I have fries with that?

[farmtruc]

Unfortunately the truck pcm doesn't support dual stages, low and high. You only have one choice for fan turn on.
I can easily add a switch to the relay to the turn the fans on.

So this brings up another question if we go for option 2. Do you guys want to have the a/c turn on the fans first or the temp/pcm turn on the fans first and on high or low.

So, when you get in your truck and start driving in the summer, you'll probably turn on your a/c before the engine gets to 185 or whatever it's set at. Should the fans be on high or low at that time.
Say you get in your truck during winter and start driving, you won't be using the a/c unless the defroster is on, do you want the engine to turn the fans on high or low.

That's why it was a hard decision to pick between the two. I know one fan will cool the engine just fine on high, and one fan will keep the heat pulled from the a/c condensor , when on high. I'm still for Option 1.

any other ideas?

thanks,

allen

[ONE04FX4]

ooops i didnt read the first to well. but i do know that my fans will stay on high for about 5 minutes when the truck is hot. especially here in houston before it cools it off. so if one fan is going to me it will always stay on. both fans will need to come on for me if it is real hot and i am in traffic.i would say 50% with the a/c and 100% with temp. since the a/c will cycle more. with both fans at 50% it will cool with the a/c. and you wont have to have on the a/c to excite the othe r fan or have to put in a swicth to activate it.

[L82gofast]

Option 1. You are right Allen, down here the AC is on all the time. I personally would like to have one fan running when the AC is on or it does'nt cool worth a crap unless you are moving (Austin=traffic).

Let me know when they are ready to ship!


Mike

[farmtruc]

Unless I start digging thru the old EET books, my setup isn't going to increase fan speed based on temperature, sounds like this is getting complicated, lol.

You can try it, unplug one of your fans and see if your truck stays cool. I bet it will. The flexlite fans have to flow more than the ls1 fans, they move a lot of air.

i'm going to start building a few this week.

btw, the fan harnesses will not have your typical fuse setup. Instead of fuses or circuit breakers, i'm going to ground the fans with a fused link just like on your starter wire might be. This will look like a normal wire, but it will break if too many amps are going thru it, just like a fuse. This setup makes it look cleaner.

thanks,

allen

[MacADaYear]

I dont use alota a/c so I guess option 2 with a manual switch would be the way to go...