well, it normally doesnt come to this, but i got a question

im hooking up an air/fuel ratio gauge. there is only one wire coming off the 02 sensor, and im pretty sure this is the one that i gotta hook it up to (its one wire how can i go wrong haha) and i just wanted to double check myself on that...thoughts?

i also am about to wire a remote fan switch, where is the sensor for this? i see one coolant sensor with two wires on it in the manifold, but i dont think thats it. i think there is one in a head somewhere, but i dunno where. anyone know where its located? or can someone tell me how to wire it straight up to the fan?

thanks guys

mike

 

The other sensor is on the passenger side head closest to the firewall on the 2.8. I think you can bypass the fan relay if you want to hook up a switch.

 

well
i went and i looked at the engine abit more carefully. there is no sensor over there on that head. im positive. (or should i say negitive hah cheap laugh)
i also followed the wires from the fan motor, and i see them going through the harness and into the fender.

so any ideas now? i see a plug where it looks like the hole should be, but no sensor and no wire either


mike

 

Weird; I thought that the 3.1's had the fan switch in the same spot (rear outer corner of passenger side head, single green wire).

Yep, tap into the purple wire for the a/f gauge. Some guys have tapped it in at the computer end, something about less resistance... but it's not like we're talking 100's of feet of wire.

If all else fails for the fan switch, just hook up a relay (which you should be doing Anyway, no matter where you tap in) and a fuse, and tap into the a/c unit's high pressure safety switch. This is on the hard line on the passenger side's main frame rail. When the circuit is broken, the fan comes on. You can see this "live" by just unplugging that two-wire connector with the engine running (don't get caught in the fan belts), pull the connector and the fan comes on.

 

can you maybe do me a huge favor and show me a schematic

btw i have one fan i dont think that makes a difference but sometimes it does

EDIT and i want to be able to keep the fan on when the engine is off.
and i also wanna keep it so it comes on when it should

maybe the sensor dont exist on my car, its a good thing it never breaks 160* hah

mike

 

Oh okay, then my method wouldn't work; the car's gotta be on in order to use the a/c high pressure circuit.

If you pick up one of those "SPDT Automotive Relays" from Radio Crap or Pep Boys or Autozone or a car stereo installation place (they'll charge double for one), you could wire it like so:

-----------------dashboard switch-----------------
+12 from positive distribution block on passenger side of rad support
...to...
1 amp fuse & fuse holder
...to...
pin 85 of the relay (magnetic coil)

pin 86 of the relay (magnetic coil)
...to...
long wire going thru a grommet thru your firewall
...to...
a switch
...to...
a ring terminal for ground, grounded to the body somewhere under the dash

-----------------fan connection-----------------
+12 from battery (or large connection at starter)
...to...
25 amp fuse and fuse holder
...to...
pin 87A of the relay (normally-open side)

pin 30 of the relay (common)
...to...
splice into fan's positive wire

I believe the fan -always- has a ground, correct? If so, the relay will just give the fan +12 volts to the motor, so you don't have to worry about hooking up a ground.

Use some decent gauge wire for the fan-side, like 16 or 18 gauge, to handle the current. You could get away with 20 and maybe even 22 gauge for the switch side, since the switch side doesn't use much power for the magnet, and, the fuse is so small (1 amp) that any short will pop the fuse anyway. But if you used thin wire on the fan side, the wire might catch fire before the fuse blew.

Keep all the connections waterproof, too... if you know how to solder/heat-shrink, that'd be the best bet. Avoid using T-taps for the splice into the fan wire; excessive vibration can cause those t-taps to actually cut thru the original wire. Best bet would be to cut the fan's supply wire in half, slide heat shrink over one of the fan wires, twist all three wire ends together, solder 'em up, and use the heat shrink again. Kinda like this:

 

My personal preference on the fan switch is a simple ground setup for the already existant fan relay, which sits right next to the fuel pump relay. It actuates via ground from the fan switch.. using a T-tap, an additional switched ground can be added no problem.

Haynes listed colors for the relay are Tan/White, Dark Green/White, Red, Black/Red.. you would tap the ground switch into the Dark Green/White. Add ground, stock relay clicks, fan turns on. Turn switch off, engine temp hits 225-230, relay clicks, fan turns on. I rarely turn mine off on my V8.. plus, the location is much closer to where the switch would be run into the dash.