Temperature Gauge Inop
 

1995 SATURN SW1 1.9 SOHC
RECENTLY PURCHASED W/ONLY 64,000 MILES .CAR IS IMMACULATE HOWEVER CLUTCH HYDRAULICS NEEDED R & R (DONE) .
My concern is the engine temp gauge on instrument cluster . When first purchased it would never go more than a stitch above cold , regardless of drivetime . After about a half hour or more the Service Engine light would come on . I immediately replace both engine temperature sensors . Finding the ECTS ( in engine block ) had cracked inside its housing and bled coolant back thru the connector . Which I removed and replaced with a solder repair . Now the gauge just "flinches" below "c" when ignition is turned on and does not register at all no matter how long the engine is running . WTH I have pinned the wires and are seeing voltage but no gauge response . Whats up ? Engine does seem NOT to be reaching normal op temp but hoses do get quite warm to touch but not really hot , which should register SOME gauge activity . What Am I missing here ???? I was sold identical brass tipped sensors for both positions . I fear there is a difference the local parts dummies are not up to date on .
1994 SL2 1.9 DOHC APPROX. 400,000 RELIABLE OTR MILES
1997 SL1 1.9 SOHC APPROX. 350,000.MILES SOLD
1995 SW1 1.9 SOHC APPROX 64,000.00
2004 BMW X3 3.0 APPROX 113,000 MILES
2003 TRIUMPH SPEED TRIPLE
2005 HARLEY DAVIDSON SPORTSTER LOW 1000 CC 13,500 MILES

Stupid question, I'm sure, but I'm just the guy to ask it. Did you check and see if there's a thermostat in the car and if there IS, is it stuck open?

+ 1 stuck open tstat. SES light is likely because PCM is sensing, based on 2 wire ects reading, that the engine is not reaching op temp w in x minutes.

I would recommend a genuine ac Delco ects all brass and the matching connector if coolant has gotten to the original connector. The parts store equivalent of this sensor is a generic sensor that is not calibrated appropriately four this application. $45.

The added electrical resistance from that corrosion will increase the resistance that the PCM sees which will cause it to indicate a lower coolant temperature then is actually present.

Additionally, 95 has two temperature sensors. The two wire sensor is the ects. The one wire sensor is also mounted in the head and drives the gauge on the instrument cluster. I can't tell you what it looks like as I have never had to remove mine, but I'm sure it can be found online. Threads in as well.

If the gauge showed some movement it is likely not a wiring problem.

You can check the codes with a paperclip the count flashes of the service engine soon light. I have a 91 to 93 Chilton's manual 4 decoding the Saturn version of the OBD1 codes if you would like me to.

And IF you do replace both sensors, DO NOT use Teflon tape on either. They get their ground through the thread connection to the block.

I already knew the t-stat was flaky . But I actually did have some gauge function until I replaced the sensor and then lost it all . It has since been corrected . Under no circumstances put any trust in the chain parts store counter boobs . You can be as specific as possible and they will still give exactly the wrong s_it ! The deal is the the ECTS and Temp Gauge Sending unit look identical but are not interchangeable . Add idiocracy to a defective part , and corroded ECTS , connector it took a minute to debug this cooling systems problems . Threw a new serpentine at it while I was there with the t-stat . NOW purrrrfection !

they are sold already t-taped . No probs at all .

1994 SL2 1.9 DOHC APPROX. 400,000 RELIABLE OTR MILES
1997 SL1 1.9 SOHC APPROX. 350,000.MILES SOLD
1995 SW1 1.9 SOHC APPROX 64,000.00
2004 BMW X3 3.0 APPROX 113,000 MILES
2003 TRIUMPH SPEED TRIPLE 9,200 MILES
2005 HARLEY DAVIDSON SPORTSTER LOW 1000 CC 13,500 MILES - WISECO - SUPERTRAPP , TWIN TECH , MIKUNI , SCREAMIN' EAGLE , KURYAKIN , HEADS DECKED

Rockauto.com or Amazon if you have prime free shipping.

Not sure how a two lead sensor can get confused w a one lead sensor..... anyway, glad you're up and running

Because two is one and one is none. Prepare!

Thanks Derf but the wagon is running like off the showroom floor after clutch hydraulics replaced with all the other fun stuff !