Temp Sensors

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Doppleganger

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I seem to need one for a gauge and another to turn on a fan. Never dawned on me they're 2 different ones. Always have had just the gauge sensor and the fan came on with the AC, but then again, I never had a dual fan setup either.

Any decent ones you might have already used? All I ever bought was VDO but they've discontinued most everything that worked.

THX
 

R Carnella

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Not sure if this helps but i used a 3 wire temp sensor.
It has two output signals,one for ecm/fan control and one for the dash Gauge.
I used this when i did my engine swap, not sure if it's helpful to you though.
I know the factory original setup has two separate sensors, one on the thermostat housing for ecm
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and another for the Gauge on the driver's side cylinder head
 

Craig 85

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Are you needing the temp sender for the Aux electric fan? It's different than the temp sending gauge. The sensor is a single wire and fits in the passenger side head. Basically a ground for the relay. Let me know if you need part numbers. I had to use a later year.
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Doppleganger

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Are you needing the temp sender for the Aux electric fan? It's different than the temp sending gauge. The sensor is a single wire and fits in the passenger side head. Basically a ground for the relay. Let me know if you need part numbers. I had to use a later year.
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YES! Thats exactly what I need. I'm going to add a jumper switch to manually activate the second fan in hot-stop and go situations (which will come on with the AC regardless).

Are these 1/2" NPT? These Edelbrock heads have a port that is decent sized.....my guess was 1/2"NPT as the paperwork says nothing. I have read other forums that guys have used mid 80's Vette sensors....?! Dunno.

On a side note.....where do they place the oil pressure sensor?

THANKS!
 

Bextreme04

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I used a cheap one from amazon. Its screwed into the passenger side head and is 3/8" NPT. I used a 3/8 to 1/2 bushing to fit in the head. I recommend you get one that turns off at the opening point of your thermostat. So this one would be good if you are running a 185 thermostat.

https://www.amazon.com/dp/B092M99DLQ/

I have a 195 thermostat and am using a 195/210 switch and my high speed fan only comes on if its warm out, I'm not running the AC(since that turns on the low speed fans), and I've been sitting completely still for a few minutes. If I'm moving at all or the low speed fans are on, it never even tries to overheat and therefore the high speed fan isn't engaged. I didn't want to put too much money into this setup, since it will all be run by the 0411 ECU when I get the new motor and trans put in. I've been running it since last April and no issues so far. I've also got a three was switch installed in the circuit that lets me set the high speed fan to On/Off/Auto(triggered by the switch in the head)

edit: added spacing
 

Craig 85

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These parts are for the OEM set up, clutch fan with OEM Aux fan. It is designed to come on as needed and has nothing to due if the A/C is on. I have the factory wiring diagram, so I can confirm this. I run a 195* thermostat on my 454.

Electric Fan Relay Echlin ECH AR225 (Photo below)
Relay Connector Echlin ECH EC85 (I had to re-pin this for my application)

Electric Fan Temp Switch - RPO 5D5
GM 10096148, ACDelco 15-2624, Airtex 1S4408, SMP TS-252, Wells SW571
(This is for a small block 1991-95) I don't know the temp range, but it works with my 454.

Replacement for 1985 truck per GM books
1991-95 454 trucks: GM 10096147, ACDelco 15-4457
Temp off/on 211/234 Degrees

Electrical connector (For 1991-95 fan sensor) GM 12126025, ACDelco PT656, Airtex Wells 1P1245, Echlin EC220, SMP-S733

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Doppleganger

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These parts are for the OEM set up, clutch fan with OEM Aux fan. It is designed to come on as needed and has nothing to due if the A/C is on. I have the factory wiring diagram, so I can confirm this. I run a 195* thermostat on my 454.

Electric Fan Relay Echlin ECH AR225 (Photo below)
Relay Connector Echlin ECH EC85 (I had to re-pin this for my application)

Electric Fan Temp Switch - RPO 5D5
GM 10096148, ACDelco 15-2624, Airtex 1S4408, SMP TS-252, Wells SW571
(This is for a small block 1991-95) I don't know the temp range, but it works with my 454.

Replacement for 1985 truck per GM books
1991-95 454 trucks: GM 10096147, ACDelco 15-4457
Temp off/on 211/234 Degrees

Electrical connector (For 1991-95 fan sensor) GM 12126025, ACDelco PT656, Airtex Wells 1P1245, Echlin EC220, SMP-S733

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THANKS very much!
 

GMC trucker

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On a side note.....where do they place the oil pressure sensor?
I’m glad you brought that up. If it’s on the TBI 454, it’s located on the lower left (drivers) front side of the engine block.
While working on my A/C system, I noticed the wires coming from the oil pressure sensor switch had bare spots and if they weren’t grounding out, I’m not sure how they weren’t. The oil pressure gauge had been operating fine. I replaced the 3 wire pig tail with a new one along with a AC Delco oil press sensor and all of a sudden the gage stops working and after a few minutes of engine running, the check engine light comes on. I’m relatively sure I spliced in the new pigtail correctly but now I’m second guessing myself. This sensor has three wires, orange for the computer, tan/white stripe for the fuel pump relay and tan/ black stripe for the oil pressure gauge. I guess I’ll have to pull my A/C brackets off again to check my splicing. I probably crossed one up. Here’s a picture of the location.
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