temperature sensor locations

Locations :

Radiator
Back of head, top
on Thermostat housing
driver side, under exhaust ?

I have a 1987 Comanche with 1994+ stuff.

originally only had the radiator and back of head sensors.

The 94' has the Thermostat. was that all it used? Did the ECU use the signal from the thermostat sensor to feed the dash gauge?

The 94 harness does not have a connection for the back of the head sensor. (yet, the 94 engine had the sensor installed) So, I pulled that sensor and installed one for an auto meter gauge.

I'm planning on using the radiator location for my electric fan sense. I was thinking of just using the original sensor. Anyone know the ON / OFF temp of the factory one? (I also have a sensor that fits that has 2 speeds, 180 & 200)

My project is not complete, so I can't test this stuff out. But I'm running wires to the locations as stated above.

Can anyone confirm my questions?

Thanks

Well, I can tell you that a '94 harness DOES have a plug for the rear of head sensor, so does a 95 ( I have both) but they changed the plug. its a plastic contraption, not the female "bullet" style connector. when mine broke, I switched it to the bullet type. Sorry,I don't have pics of them.
IIRC the rad sensor turns on around 180
Are you splicing harnesses, or swapping everything?

The 94 should have the sensor at the back of the head for the gauge. The one in the t-stat is for the PCM. IIRC they did away with the one at the back of the head in 97 and used the PCM to control the gauge. .

Talyn said:

The 94 should have the sensor at the back of the head for the gauge. The one in the t-stat is for the PCM. IIRC they did away with the one at the back of the head in 97 and used the PCM to control the gauge. .

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this.

pre can bus clusters were still dumb gauges with senders.

the renix PCM got it's information from block mounted sender. HO ones it's in the water outlet.

the one in the back of the head has never done anything other than be for a gauge.

well, okay then, that makes sense. The 94 Head had a sensor, and there is a connector with just one wire, near that sensor. But, the connector is not the normal push on type, in fact, I can't see how it'll fit the sensor...

So, I'll put back that back sensor and tap the thermostat housing for the auto-meter gauge sensor. I'll put on a new push on fitting for the back sensor, I ordered a few new electrical fittings.

Thanks for your all's help, saved me from having to re run new wires. I like my electrical clean n tight.

So, just to clarify, the radiator sensor is NOT needed for 94? And looks like its ~180?

(Note, basically its just a 87 body, everything else was pulled from a 94. Dash, whole harness, engine (stroked), transmission, T-Case, axles,,,,) Had I known what I know now, I would have used an 97 or newer for ODBII.. I may swap it to a 1999+ in the future. But I do like the 87~90 dash layout.

the one in the radiator is for the efan. It was not pcm controlled in the renix. leave it, and leave it hooked up to control the efan. it's standalone.

The one in the back of the head, it's threaded the same as the renix head. just swap the sender for the one that matches your harness.

the 94 PCM needs it sender hooked up to the tstat housing. any HO housing will have the hole.

that will ru the fan, gauge and PCM. no need for anything aftermarket or rewiring any of the body harness.
drop your 94 engine/pcm/harness in the engine bay and drive off.

87manche said:

the 94 PCM needs it sender hooked up to the tstat housing. any HO housing will have the hole.

that will ru the fan, gauge and PCM. no need for anything aftermarket or rewiring any of the body harness.
drop your 94 engine/pcm/harness in the engine bay and drive off.

Click to expand...

Okay, so to confirm, the sensor in the thermostat housing feeds the PCM. The PCM uses that to control the E-Fan, Dash Gauge, and engine management, right? (on 94)

So the 94 does not use the back of head, or radiator locations?

If that's the case, then I'll run my E-Fans off the radiator and aftermarket gauge off the head.

(although, I just got a high flow thermostat housing, and tapped a 1/8th hole for sensor..)

DaKing said:

Okay, so to confirm, the sensor in the thermostat housing feeds the PCM. The PCM uses that to control the E-Fan, Dash Gauge, and engine management, right? (on 94)

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The one in the tstat housing is for the PCM, but the PCM does not control the gauge. The gauge is motivated by the one-wire sender at the rear of the head.

So the 94 does not use the back of head, or radiator locations?

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The gauge is motivated by the one-wire sender at the rear of the head. 94 radiator does not have a sender outlet (RENIX did, HO does not).

If that's the case, then I'll run my E-Fans off the radiator and aftermarket gauge off the head.

(although, I just got a high flow thermostat housing, and tapped a 1/8th hole for sensor..)

Click to expand...

Good place for it, I drill another hole in the tstat housing for my efan setup

ehall said:

The gauge is motivated by the one-wire sender at the rear of the head. 94 radiator does not have a sender outlet (RENIX did, HO does not).

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91 radiator will have the plug for the renix efan sender. I've done the conversion more than once.