has anyone ever heard of this being in the block just above the oil pan on the pass side? I've been looking on the pass head, and feeling around thinking that it might have broken off. Well I went to the store to get a new one so that I could see what the connector looked like and I found the plug and something that resembles the switch just above the oil pan on the pass side in the block. Could this be my missing switch. I've replaced everything else in an attempt to get this friggin fan to work.

 

On the passenger side, (at least on my 89 5.7L Iroc) there is a heavy duty fan switch mounted in the engine block near the starter. It has a single wire connector that resembles the connector on the proportioning (combo) valve beneath the Master cylinder. There is also a knock sensor mounted in the same general area with a different type connector.

 

I just had to change my Radiator Fan Switch, There is a switch next to the starter, but i don't think thats the one you need to change, i do believe it's the one on the driver side, next to the front most spark plug. Should have a singe green wire comming from it. That green wire should rull back to one of the two relays next to the master brake cylender (mine was the relay on left from inside car) ... i think this is where you need to look.

to be honest, i'm not sure what the other switch is for, i don't see it on any of my other wiring diagrams. But for the radiator fan switch, it's on the driver side.

 

Serpentineocean,

The one you referred to by the #1 sparkplug is the temp sensor for the temp guage on the instrument panel.

 

Holy Crap!!!!??? are you sure? cus i asked like 3 places, and they all gave me the same part, which looks nothing like that one thats next to the starter, it looked alot like the one next to the #1 plug. lol.. plus it had the green wire going to it.....

come to think of it, my temp gauge has been acting weird. Like, it wasn't moving off of 100deg, untill it overheated, then it would be off the scale-hot .....

crap crap crap....


EDIT: -Yea, i'm thinking about it, and you have to be right, cus i removed a variable resistance sensor, and replaced it with a straight on/off sensor.. which is why when it got hot, it would show off-the scale hot..... *crying* .... lol.. now at least i got somthing to do this weekend....lol

 

Hey, if that thermostat is disconnected, would that mess w/ my ECM's timing or somthing when it warms up? cus i thaught it was my spark plugs were gapped wrong, but i'm getting a weird idle speed (and it's a bit more -chunky- then before i did all this) and also after a little bit it seems to missing every now and then... very annoying....

(if thats the dash temp sensor, whats the sensor directly left of the coolant thermostat on top of the intake manifold?.. it's got 2 wires comming off of it)

 

The one with the two wires is the coolant temperature sensor and that one is connected to the ECM and affects the way the engine runs. For my heavy duty fan switch, I had to go to the local dealership to get the right one. The aftermarket (at least some) versions are designed around the older engine designs and don't use the proper connections.

 

The temp senser for the instument panal in on the drivers side head. The Fan switch is on the passenger side head. The knock senser is on the block by the starter. The CTS computer temp senser is on the water neck, the only one with 2 wires.


This is how my 84 Z28 is setup.

 

Yea, thanks guys!! i got it all straightend out this weekend. Although the fan switch still doesn't work!! I guess i'll buy another one and try it again. I know the relay and everything works because i can pull the wire straight from sensor and touch it to the block (ground) and the fan kicks on.

ps- damn those engineers, why have 2 similar size sensors w/ 1 green wire ...lol

 

here is a pic of one

 

I ask why have three sensors instead of just one. This is friggin annoying. I'm about to hard wire the fan to the ignition and be done with it.

 

Actually we have Two sensors and one switch. 1Sensor for The Temp Guage, 1 Sensor for the ECM, one Temp switch for The Fan.

 

That's all good and well but we should only really need one sensor to tell the ecm what's going on and it should control the gauge and fan.