Finishing up my flex-a-lite vsc install on my truck and have a question regarding the A/C input switching. I read james' great install instructions on fullsizechevy.com but am unsure about which wire to use to turn the fans on during A/C operation. Obviously it has to be either the green or black wire coming out of the a/c compressor and I think that if i use the green wire that it would go to the #6 terminal on the VSC controller (for a positive signal). Can anyone verify this? Also w/ regards to the manual on and off switches, is the vsc looking for a +12 signal or ground.

I know on my 01 it was green. http://james.jaguar.net/agreif/fans/fanstech.htm

The manual over-ride switch needs a ground. Use a single-pole double-throw center/off switch for that, works great. (SPST) I use a switch like that and have it set up so that up is "override on", center is "normal operation" and down is "override off".

For the A/C I am pretty sure is was the green wire. Try both lugs on the VSC for the A/C clutch. Plugging into the wrong polarity on that won't hurt anything.

It's the green wire and it goes to the + A/C input.

Must be the day to install electric fans. I installed mine this morning. It's the green wire, 12 volt positive signal.

Must be the day to suck in a bird thru the grill of my truck this morning.
It sure planted some pretty feathers in the AC condenser

Me too man! I washed and waxed my truck yesturday, and I'm driving back to Lubbock and a damn bird screws everything. He splattered all over my white grille, condensor, and the side of the radiator. Luckly he missed the aux trans cooler! Damn birds......

I hope it was one of those damn black crows/grackles or whatever they are called.
They are always on top of things. They like cars.

350SS wrote:

Finishing up my flex-a-lite vsc install on my truck and have a question regarding the A/C input switching. I read james' great install instructions on fullsizechevy.com but am unsure about which wire to use to turn the fans on during A/C operation. Obviously it has to be either the green or black wire coming out of the a/c compressor and I think that if i use the green wire that it would go to the #6 terminal on the VSC controller (for a positive signal). Can anyone verify this? Also w/ regards to the manual on and off switches, is the vsc looking for a +12 signal or ground.

You don't have to get to the GREEN wire at the compressor. There is a bundle of wires comming up from under on the driver's side near the battery cable junction box. It's in there.

Up and running w/ A/C request. I tapped into pin 25 on the white ecm connector. Everything is working properly now, just need to get that switch that James was talking about for the manual on/off function and I'll be set. Thanks for the help.

Max

I finished up my fan install two days ago, and yesterday the fans quit working. I checked all conections and found that the ground wire for the whole system had burnt up at the connector to the VSC. I originally used 14ga wire which may have been too small so I switched to 12ga wire and a weathertight seal connector. I'm running two permacool 14" fans rated at 9.5 amps each. Should I be having this problem? Is there something else that I should be looking at for reliability?

14 gauge sounds pretty small for cooling fans. I used 10 for the main power line for both fans, and 12 for the individual fan motors for my FAL fans. Use a wire sizing chart such as this one- http://www.westmarine.com/pdf/0660_ETRIC_MC04.pdf to see how big of a conductor you need. Don't forget to take into consideration the derations noted in that PDF, mainly the temperature deration of 15% for engine compartment spaces.

350SS wrote:

I finished up my fan install two days ago, and yesterday the fans quit working. I checked all conections and found that the ground wire for the whole system had burnt up at the connector to the VSC.

So just the wire was toast? After just about 2 years I have had the negative post for the fans go out on the VSC. The post is just dead.

Andrew

P.S. Great link Patick, thanks.

yep, the wire right at the end where it was stripped and crimped into the connector was burnt and the insulation was melted. is that what's going on w/ yours or is the vsc burnt out?

Man ever since I mentioned how hot my fuse holder gets, it gets holder. Great, not knock on wood, pound on wood.
Im driving from dallas to the airport (with only 2 lanes, far right lane a damn broke down transam). I get home, touch fuse, HOT AS HELL. FAL is sending me a new fuse. Those guys are nice.

NO the VSC was actually toast, and then when I went to pull the #1 negative out today look what happened. Sweeeet.



Andrew

Sorry man, we knew that's what happened just from talking. It's those damn lugs terminals. Connection wiggles loose and becomes a resistor which heats up and melts the solder inside.

I see by the number of heat sinks you have the older vsc.

Correct. I'm getting a replscement froma guy on tech that had a used one. it was $10 vs the new 80, so I'll see if that works and if not I'll just pony up and get a Nelson harness. Really do need to put a rocker "ON" switch in to make sure I can run these even when the VSC does poop out.

Sounds like your problem 350SS is just what patric described, undersized wires.

Andrew

IT all depends on how many amps the fans draw.
My truck's FAL 250s must draw like 40 amps or something (newer VSC).
But the Camaro had its stock fans and the older VSC, and only drew like 10 or 15 amps.
Need some sort of bigass resistor to keep the fans from spinning so fast and drawing all that power.