Warning to manual fan mod methods

[BadAzzRS]

I discovered something when installing a manual fan mod that is not declared well in any online intructions.

If you notice, depending on where you tap into the J and H, they may be already hot wires. Use a volt tester to see if they are, and if they are DO NOT tap into any othersources for power. I blew fuses LOL.

Really all you should need to do is tap into the J and H wires, them to a switch, then run a ground to the switch, and thats it. your done, you shouldnt have to run another hot wire, you will cause problems, may infact blow your car up.

[mjparme]

I have never seen any online instructions that say to run another hot wire to the J and H wires.

As you describe in your last paragraph you wire J and H to a switch and run a ground to it. That is it. No need for another power source.

[CAMAROWIDBASS]

when i first tried to do mine when i crossed 2 wires sparks flew left and right and i blew fuses also.

[jaday]

yeah, I agree with mjparme, I don't recall seeing instructions that you need to run wires to any other power source, but anyway, the fact is, I guess we've all found out that we don't need to have it...

[MustangEater8251]

OF all the manual fan switch ideas and everything...


On my 94, all I ever did was connect a wire to the battery terminal, to a 2 wire toggle switch, to a inline fuse holder(with 25 amp fuse) then spliced it into the "+" part of the fan.

worked fine, and if you really didn't need a write up just understand that + is hot and Negative is not hot, and you need both for the motor to work.

I took it off because i wasn't really useful on my 94 since it never really ran hot.

[slow]

on Connector C-100, 10 pin black, there should be no +12 volt wires for the fan, on any 93-2002 f-car.

if you have true voltage at pin H and J, your in the wrong connector, or have a funky car.

there will be some voltage present, if tested by a meter, as it is a relay coil (coil of wire) so voltage will be pickedup by a meter.

I've probaly done every manual fan mod available on the net, on various cars , but settled on one like the SLP style one, (no splicing, no ses lights, (bigger problem on the older or the LS1 cars) and easily returned to stock.

those wires go to the computer, and provide a ground, so there is NO reason to put +12 votls to them, the only time you need to tap into power for a fan switch, is if you want it lighted. And even then, that is on the back side of a diode, to prevent backfeeding (LED = Light Emmitiing diode)

Ryan

Ryan.

[BadAzzRS]

http://users.oco.net/xero/fanmod/

the first diagram shows a 12v source from the cig lighter, which i have no clue why it is needed. i assumed my wires were not powered by when i hooked them up, sparks flew, i was quite pissed, i hope this isnt the reason my ABS module is dead.

[BadAzzRS]

also what i dont get is why he has the dark green\blue wires running to the negatives of the LEDs, its a hot wire LOL terrible diagram, he should be slapped for posting that.

[Wicked 3800 V6]

I thought the xero diagram / writeup was perfect. Keep in mind it needed to have a lot so that the LEDs received power, not just the fan relays.
Aside from those, it should be just the blue and green for low / high (not sure which is which) and a ground.
-Rob

[slow]

Originally posted by BadAzzRS:
also what i dont get is why he has the dark green\blue wires running to the negatives of the LEDs, its a hot wire LOL terrible diagram, he should be slapped for posting that.

huh?

the blue/green wires ARE the negative of the fan relays, the computer provides a ground to turn the relays on. The only hot wires are not touched in the fan mod, you just add a ground on the ground side of the factory relays using pinc H and J connector C100

so you DO need to connect them to the NEGATIVE side of the LED, as they are the GROUND

the +12 is ONLY for the LED in that fan method, and that is why it is not needed for the basic fan swithces, that just ground the pins.

Simple schematic of what is necessary to make the fans work

Low
Pin J --- Ground -- low speed only.

High
Pin H ----\
Pin J ----/----- ground -- (high speed operation)

note: you may get ses lights on some cars, using this method, the newer V6's don't seem to throw a fan code easily, but this method will throw a code on a ls1 or 96-97 LT1 vehicle, and possible older V6's as well. This is only part of how slp does it, there is logic to add into the circuit, to prevent ses ligths.

Ryan

[ April 14, 2004, 06:41 PM: Message edited by: slow ]

[BadAzzRS]

Well, I didnt do the LED's in the end, but hell, the LED's dont suck up that much power.

All i did was run the H and J wires to a switch
then a ground to the switch
then LED's
as soon as i ran a 12 volt wire to the switch, sparks flew and a fuse popped.

I removed 12 volt wire, everything worked fine. LED's lit up. But i took them off because i did not want them really.