LIL SS

iTrader: (9)

I am planning on doing my own fan mod this weekend. I am planning on buying a switch that has 3 prongs (Common, Normally open, Normally closed) and wiring it in. This is my wiring idea..

Power from Battery goes to Normally Open
Power given from the stock system to the fans goes to the Normally Closed
Common goes to the fans

Plan is to cut the power wire to the fans just before the fans. Extend it into the cab connecting to NC contact. Common goes back to power input for the fans. New wire from the battery to the NO contact.

If I am right, in the off position the fans would work normal, turning on when the computer sensed they should be on. In the staging lanes or on the street turning on the switch will turn on the fans when I want.

My questions:

1) How many amps do our fans pull?
2) Do our cars turn on 1 fan at a time or is it a high/low speed thing and at what temp (Stock programming)?
3) Are the fans wired in series or parelel?
4) Is there anything else I am missing?

Thanks guys in advance..

TA_2001

Here is yet another way to do this..


http://ls1info.com/article.php?sid=171&mode=&order=0

I am going to do this in febuary when I install
at 160 Thermostat..

Jacobi

I did my fan mod with just a switch and some wire from a hardware store...took maybe 2 hours, maybe!

LIL SS

iTrader: (9)

[quote]Originally posted by Jacobi:
<strong>I did my fan mod with just a switch and some wire from a hardware store...took maybe 2 hours, maybe!</strong><hr></blockquote>

What did you do, and how? The above is very vaige..

Onyx LS1

iTrader: (5)

Don't hard wire it or it will burn up on you. Trust me! <img src="images/icons/wink.gif" border="0">

LIL SS

iTrader: (9)

[quote]Originally posted by Onyx LS1:
<strong>Don't hard wire it or it will burn up on you. Trust me! <img src="images/icons/wink.gif" border="0"> </strong><hr></blockquote>

I take it you hard wired the fans.. How did you do it? Did you take in to consideration the fans comming on under normal conditions and having 2 power sources to the fans? That is why I am thinking a NC/NO/CO switch is needed to eliminate the stock circut while the switch is in the on position..

I think doing it the way I am talking about would run the fans at high speed, keeping the stock wiring out of my loop. I have a quick drawing if someone would like me to e-mail it to them. I want to make sure it will work right.

gwj

Do not wire the fans from any hot wires. The way the pcm turns the fans on is to put the relays to ground. A 3 position double pole switch will give you : Fans off, or, Fans on low speed, or, Fans on high speed. When off the fans will function normally. You can tap into the wiring harness on the passenger wheelwell and run the wires inside through the firewall behind the computer.

LIL SS

iTrader: (9)

[[B}Do not wire the fans from any hot wires. The way the pcm turns the fans on is to put the relays to ground. [/B]

B]You can tap into the wiring harness on the passenger wheelwell and run the wires inside through the firewall behind the computer.[/B]

I am not sure I understand what you are saying. Should I be hooking the switch into the ground side of the fans instead of the hot side, completing the circut?


A 3 position double pole switch will give you : Fans off, or, Fans on low speed, or, Fans on high speed. When off the fans will function normally.

Where do you splice it in? Is it posible for you to do a quick drawing of what you mean, scan it and e-mail it to me? I don't know if you have a scanner..

gwj

This is from memory and for the 2000 ECM pin-outs.
I tapped into the wiring harness that runs over the pass wheelwell to the computer. To do a quick test, you can pull the large connector apart on the wheelwell and look look for the pins that correspond to the Dark Green wire (low speed fan relay control) and the Dark Blue wire (high speed fan relay control.
With the ignition off, take a probe or wire and touch the Dark green wire pin and put the other end to ground. The fans should come on low speed.
With the green wire still to ground, take another probe or wire and touch the pin that corresponds to the Dark blue wire and put the other end to ground. Fans should now come on high.
In other words the Dark Green wire to ground will run the fans on low. Both the Dark Green AND the Dark Blue to ground will run fans on high.
Don't have to cut any wires, just use the crimp-type connectors available at Radio Shack.I tapped into the wiring harness at the rear of the wheelwell and thus could route the wires in existing split-cover up to the computer. If you take the computer MOUNT loose you can get some wiggle room and there is a grommet behind and down that you can snake the wires inside behind the pass kick panel, then route through the dash.
Incidentally, there is a good ground source behind the pass kick panel you will see wire(s) bolted to.
I don't remember the switch wiring but can look at it tomorrow maybe if you need help. A 3 position dbl pole/dbl throw will let you wire for off, low, or high speeds. Good luck, it doesn't take very long to do. My switch is mounted to the left of the "CAMARO" lettering on the console.
A small switch will fit into an empty plug there, but the larger one I used took gluing in a drilled piece of black plastic.

gwj

I should add that if you turn the switch on while the fans are already on, sometimes it will set a code. Doesn't harm anything, though.

LIL SS

iTrader: (9)

GWJ,
Very cool, well thats what I plan too do, keep it cool. Thanks for the info!!

More car work this weekend.. <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" /> <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" /> <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" />

gwj

No problem. Just remember the wire colors correspond to the 2000, not sure if other years are the same. (I think so, although the ECM pinouts might be different). You can test at that connector on the passenger side fenderwell and find them before you start wiring, though.

Red2000SS

[quote]Originally posted by gwj:
<strong>No problem. Just remember the wire colors correspond to the 2000, not sure if other years are the same. (I think so, although the ECM pinouts might be different). You can test at that connector on the passenger side fenderwell and find them before you start wiring, though.</strong><hr></blockquote>

I did the fan mod as gwj described it - tapping to the wires going to the PCM and grounding them through a DPDT switch. The other way to do it is trying to provide some alternate method to supply power to the fans. This requires a hot wire and the fans draw some serious current ~20-30 AMPS!. You will need heavy duty wire and probably an extra fuse.

Using gwj's method of grounding the PCM wires, only draws a couple hundred milliamps (I measured).

Other notes:
Mine is also a 2000 so you might want to check the wiring diagram in the Helms manual or experiment if you have a different year.

I have a double pole double throw switch - push it left and the fans come on low speed, in the middle the fans are controlled by the PCM as normal, push it right and the fans come on high.

I have found that the only time I set a code is if I have the switch on (left or right) when I start the car. I think the computer does a diagnostic check & will throw a code if it detects these fans on at startup when it thinks they shouldn't be. I have NEVER thrown a code as long as I make sure my manual switch is off when I start the car.

I mounted my switch by drilling a hole near the lighter. I also mounted a LED near the switch that comes on anytime the fans are on. If this LED is still lit when I turn off my car, I know I need to turn off my manual switch, or I will run my battery down soon...

Good luck.

LIL SS

iTrader: (9)

Thanks again guys.. The fan mod is done as GWJ has described. Wiring is the same on a 2001 car FYI.. <img src="graemlins/gr_cheers.gif" border="0" alt="[cheers]" />

LIL SS

iTrader: (9)

Thanks GWJ for the post. Red2000 thanks as well.. The fan mod is done and working. Just an FYI for everyone 2001 has the same wiring colors..

Tin Indian

[quote]Originally posted by TA_2001:
<strong>Here is yet another way to do this..


http://ls1info.com/article.php?sid=171&mode=&order=0

I am going to do this in febuary when I install
at 160 Thermostat..</strong><hr></blockquote>
________________________________________________

Hey, thats the old fan mod instructions I originally wrote about 3 years ago!

Ron, <img src="graemlins/gr_cheers.gif" border="0" alt="[cheers]" />

gwj

You can learn some useful stuff if you stare at the Helms manuals long enough!