Hi there, here are the specs Camaro RS '91, 305 TBI.
The fan only comes on when the A/C is on and the engine overheats.
I could only find 3 relays, one on the passenger side and two right beside the master cylinder, which one is the fan relay?
I don't think it is the relay as the fan comes one when A/C is on which engages the relay, right? I checked all these 3 relays last night and they all worked fine.
The fan switch is somewhere on the passenger side at the bottom of the block, I can 't see it but I put my hand in there and felt a "sensor" now I am not sure if that's the fan switch or the knock sensor. It feels like a fat cylinder and the cable going to it show 12V between the + battery terminal. The fan switch I bought doesn't seam to be like that.
Where is the knock sensor located?
Am I looking (feeling) at the right thing, if not where is it and how do I change it, do I have to jack the car up and do it from underneath?

Any comments, links, etc are welcome.

Thanks a lot for your help.

F-22

:lala:

 

Hey man, I cant help ya too much but....


Your gonna have to go underneath the car.

And heres a pic for ya...

 

yup, theres very little doubt its the fan switch. Had to change it on mine a year ago. Gotta go under the car and get to hit like Iroc said.
~Tim

 

That picture is great, but if you need a description then it's between plugs 2 and 4 above the starter motor. The knock sensor kind of looks similar but it's not nearly as far up into the engine as the switch. You'll know you have the switch when you unscrew it and coolant comes out. If no coolant comes out then you have the knock sensor. You definitely need to jack up the car for this one.

 

I wouldnt quite say that....the knock sensor is also in a coolant passage and will pee all over you ;-)

 

You guys are great.
So I guess I have to flush the cooling system before I start doing anything?
When I put the switch in should I use anything on the thread?

The sesnor I felt was more like a cylinder in shape and about 1" diam. does that sound like the knock sensor?

F-22


PS How did you add pictures at the bottom of your postings? You can tell I'm new at this.

 

The fan switch on my 91RS TBI is on top of the thermostat housing. It has a cisrcular plug on it with a single wire attached to it. If you ground this wire, your fan should turn on. Mine did so I know I have the right wire. I tapped into this wire and used a mechanical adjustable thermostat switch to turn on the fan at 180 degrees. It works pretty good so far and it's a relatively easy mod. I hope this helps.

Rene

 

That picture posted by IROCTHE5.7L is my 91 RS's Jet-Fan Switch I posted awhile back. Are you sure your car is a 91?

 

I'm sure that it's a 91. What other year would there be with a fan switch on the water outlet housing?

 

In "91" all RS's and Z28's came with these new ground effects, that's one way you can tell if it's a "91" or not.

 

My RS has the same ground effects. Let me give more information on this. The water outlet has a threaded port for (I assume) the fan switch. This switch has only one wire connected to it. Grounding this wire turns on the fan when the ignition is on. Below the water outlet to the left is another sensor which has 2 wires attached to it. I think this one is for the computer and the temperature gauge. If the switch threaded into my water outlet is not the fan switch, does anyone know why the fan turns on when its wire is grounded? I went to the dealer to see what their fan switch looks like and it's identical to the one I have that's threaded into the water outlet.

 

Here is a pic of the thermostat housing. The thing on top with the green/white wire is the fan switch. The one below that to the left with 2 wires is for the ECM/gauge. Please, correct me if I'm wrong.