I thought it was in the radiator. Maybe I'm wrong?

Closed loop converters , from what I read, use an open loop tstat housing to relocate the temp sensor to the tstat housing itself.

I pulled my radiator a week ago, no sensor was on it. Am I missing something, or has my brain melted my thoughts together with some other project?

 

Sensor on radiators fan switch,cts on block behind drivers motor mount along with knock sensor on 4.0

 

That'd explain my lack of sensor.

PO took that off, wired Efan to switch, AC is long gone.

This is a relief. Thanks Gary, thought maybe I'd finally lost it.

 

This would not explain mental state.lol

 

87-90, (at least)....

Top left, rear, on the head for gauge/ light. (grounding it's wire activates the gauge, or lights the light)

Engine coolant for Puter', on left side of the block, down under. (3,400 ohms @ 70*, 185 ohms @ 212*) Unplugged.

E-Fan switch (217*), Backside, left on Radiator. Connecting it's two wires turns on the fan.

 

Temp SENDER is in the back of the head on the driver's side. Coolant temp SENSOR is located on the lower driver's side of the block. The fan SWITCH is screwed into the driver's side of the radiator.

 

RENIX has three:
- Driver's side rear of cylinder head. This drives the IP gage/indicator lamp.
- Driver's side radiator tank. This is the thermal fan switch to turn the e-fan on & off in response to temperature.
- Driver's side of block, above oil skirt, behind exhaust manifold. This generates the coolant temperature signal for the ECU.

The one in the head is a dedicated OEM part.
The one in the radiator may, I believe, be replaced with a Peugeot or Renault part to get a bit lower "on" temp for the fan.
The one in the side of the block is a standard GM thermistor.

 

What temps the factory one set at .Don't by chance got the lower setting ones part/info number ...

 

You mean the radiator switch? I have heard 218* numerous times, but while dinking around in the FSM for 1990, I found it says 210*. That's not at the top of the radiator though.

 

Haven't tested, don't know. The other part info, I think I saw at NAXJA.

(It's a TFS threaded M20-1.5 - same as the oil filter, oddly - and probably used on Renault, since that's who AMC was partnered with at the time.)

 

IIRC, the post I read referred to a Peugeot switch. You know, the other supplier of crappo transmissions.