which one is my ‘ect sensor sending unit’?

[colleen]

hey all, thanks in advance for replies. can’t tell which one of these is my ‘ect sensor sending unit’. note that I am not referring to the temperature switch on the thermostat housing.

my Chilton says I can test the sensor by disconnecting the cap to the sending unit, grounding it with a test lead, this should make the dash temp gauge operate.

2 pics:

green-capped unit, hose is upper radiator, can see distributor to top left, valve cover top right.

grey-capped unit, about 5″ behind the green-capped one. picture is slanted.

thanks!

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• radhose.JPG
• underdist.JPG

Topic

[college man]

usually the sending unit sensor has one wire.
What car is this? year,make,model,engine size

[colleen]

96 accord 4cyl vtec m/trans

ok my bad. the Chilton doesn’t say to disconnect the cap. it says:

‘with the ignition switch off, disconnect the wire from the ect gauge sending unit, then ground it to a place on the engine block or other known good ground with a jumper wire. ‘

after then turning ignition switch to on, the gauge should move toward hot in a smooth manner. book adds to turn ignition switch OFF before gauge reaches hot or could damage gauge.

this does appear to be a method of testing the GAUGE itself. now another question, would this test basically condemn the sending unit if the needle smoothly rolls to hot? (and the dash gauge is not working under normal operation. I know this is a simplification considering there are probably other factors involved, like thermostat).

so yes that makes more sense now that you say it is a single wire. In between the two ‘sensors’ that I thought may be the ect sending unit is a single green/yellow wire connected directly to the cylinder block. you can see it in the previous pictures, in the middle. the old foam boot covering it will probably not deal well with tampering so instead of messing with it right now I will wait for confirmation that this is my wire.

here’s another pic:

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• grnyell.JPG

[colleen]

here’s another pic, I ended up peeling back the rubber cover on the wire to expose this clear plastic connector. now stumped as to how to unlatch it w/out breaking it.

Attachments:

• ectsend.JPG

[college man]

did yo unplug the sensor wire and ground it to see if
the gauge moved to hot?

[colleen]

no, I haven’t got that far 🙁 I need to disconnect the plastic connector (I assume) and don’t know how. I’ve never seen a connector like this before. it looks like I could pop one end up, but I don’t want to break the connector. I don’t know how else I would access the terminal point of the wire itself w/out opening this connector.

[college man]

[quote=”adamint” post=85682]no, I haven’t got that far 🙁 I need to disconnect the plastic connector (I assume) and don’t know how. I’ve never seen a connector like this before. it looks like I could pop one end up, but I don’t want to break the connector. I don’t know how else I would access the terminal point of the wire itself w/out opening this connector.[/quote]

Pull the connector plug. It looks like this.

http://www.1aauto.com/1A/coolant-temperature-sensor/Honda/Accord/1ATSU00007/474659-1996?utm_campaign=gb_csv_br&utm_content=TSU&gclid=CJLhhdiuirwCFU9p7AodsgsAvw

[colleen]

hooray, my dash temp gauge works! that’s good news, didn’t want to replace the gauge cluster. this single wire comes straight out from where its connected, I held the plastic connector with a pair of pliers, and took a small pry bar leveraged in between the plastic connector and the metal sending unit assembly and just popped the unit out. I’m glad I didn’t try to pry open the plastic connector.

i cut the end off a low voltage test lead, stripped about an inch of plastic casing off the cut end, twisted the exposed end and doubled it over, and shoved that into the plastic connector. clipped the alligator clip on the other end of the lead to a bolt head on the cylinder block. then I put the ignition to on, and the needle went straight to hot in less than a half second. you’re not supposed to let it reach the hot mark, it could damage the gauge, but oh well.

now I know the gauge works, the manuals say to test the resistance of the sending unit itself.

here’s the procedure if you don’t have a manual:
*with engine cold, use an ohmmeter to measure resistance between the positive terminal and the engine (ground)
*check the temperature of the coolant
*run the engine and measure the change in resistance with the engine at operating temperature (radiator fan comes on)
*if obtained readings are substantially different from spec, replace the sending unit

specs:
temp 56c(133f), resistance 142
temp 85c(185f)-100c(212f), resistance 49-32(ohms)

now I am a rookie (obviously! ha ha) and I can’t see how if your sending unit passes the resistance test what else you would check after that. anyway, I’m going to go ahead and do that but I can’t run my car right now cuz some fuel components are disconnected so its gonna have to wait. will be using my harbor freight cheapie multimeter that I got for FREE with a coupon there so hope its up to the task.

EDIT:
well, for the first time since owning this car, I’m getting a response from the dash temp gauge while the car is running. After replacing my thermostat, coolant temp switch, and ‘shocking’ the ect sending unit back to life, not sure which one did it, it works. Never went as far as measuring resistance on the unit itself. After peeling back the rubber on the connector (unnecessarily), I had to rig something to cover the wires again so I took an inch of plastic tubing, the pre-cut kind designed to wrap around wires, put that over the plastic connector, gave it a few wraps w/ electrical tape, and am currently hoping the tape doesn’t melt. Actually have duct tape over some air box fittings which disintegrated when I pulled the air box out to work on the thermostat, too. don’t laugh.

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