Which coolant temp sensor sends to the gauge?

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#11

12-31-2013, 03:26 PM

Brenton Thornicroft

Join Date: Dec 2013

Posts: 3

Hey

Does anyone know the OEM part numbers for the temp switch A and temp switch B? I'm trying to buy replacement parts, but can't determine which ones I need on here:
RockAuto Parts Catalog

Thanks

#12

01-01-2014, 08:59 AM

poorman212

Super Moderator

Join Date: May 2010

Location: Youngsville, NC

Posts: 11,832

You can go to one of the many online Honda Dealers websites and look up the parts and get the part numbers.

Try Majestic or Bernardi, there are many more out there.

If you find it hard to get the part numbers (the catalog takes a bit to get use to), give us the exact details of your car and we can help you out.

#13

05-12-2015, 02:01 PM

pb92109

Join Date: May 2015

Location: Connecticut

Posts: 3

Re: [Engine coolant temperature sending unit. Is on the side of the cylinder head facing the passenger side of the car. It is the closest sensor to Temp switch B. It only has one wire going to it. It controls the temperature gauge in your car, so its signal (resistance) varies.]

Is this sending unit smaller than the other 3? Is it right under the distributor housing? Is there a best practice to access, remove/replace this unit. It looks tough to get at.

Also, can anyone inform me what the OEM part # is for this particular unit if if is indeed different than the other 3? Parts guy sold me the larger one.

Thanks in advance!

Last edited by pb92109; 05-12-2015 at 02:04 PM.

#14

05-12-2015, 07:13 PM

Joyce.Tyler541

Newest Of Newbies

Join Date: Aug 2014

Posts: 21

Quote:

Originally Posted by pb92109

I would test it before you replace it because its a super easy test.

Unplug the wire to the sending unit, ground it out with a t pin and a lead and it should go all the way to hot.

With it not grounded it should do the opposite.

If this test works then you know the wiring to the sensor is good. If not, then you have an open or a short in the circuit or you have a problem with the gauge itself and you just saved yourself some money on buying a new sending unit

#15

05-12-2015, 07:23 PM

pb92109

Join Date: May 2015

Location: Connecticut

Posts: 3

Excellent advice - I did some digging and found the correct part, so I bought it. I will do this test tomorrow and return the sensor if the original is still good. Appreciate it!

#16

05-13-2015, 08:39 AM

JimBlake

Super Moderator

Join Date: May 2006

Location: Wisconsin

Posts: 18,398

When you ground the wire, have someone watching the gauge. The shop manual warns that if you leave it go until the gauge pegs high, you can damage the gauge. You only want to verify that the gauge moves towards the high end.

#17

05-18-2015, 04:05 PM

pb92109

Join Date: May 2015

Location: Connecticut

Posts: 3

Joyce.Tyler541 and Jim Blake: Thank you for your help with solving my problem. I always like to hear a success story, so here goes. Replaced radiator. replaced thermostat. Cooled my ego off for a day because I didn't replace the old thermostat gasket and of course I misaligned the 2 invisible nubs on it, causing it to leak. Bought new thermostat gasket, bought new engine coolant temperature sending unit, performed the easy test suggested by Joyce.Tyler541 and determined the gauge and wiring were good. Replaced sending unit as planned, reinstalled thermostat with new gasket. Everything is working. nothing leaks and I can trust the engine temp dash gauge.

PHEW. Now onto the next car - but which one is the priority???

#18

08-26-2015, 07:36 PM

scrapmetaljoe

Join Date: Aug 2015

Posts: 8

Quote:

Originally Posted by PAhonda

Thanks, you can put that information in your signature, so you never have to remember.

Anyway, there are four sensors.

Temp switch A: On thermostat/lower radiator hose housing. Has two wires and a green plug. Will turn on both fans when coolant is above 200F when the engine is running. It is an on/off switch.

Temp switch B: On the housing where the upper radiator hose clamps to the engine. Also has green plug and two wires. Will turn on one fan when coolant is above 223F when the engine is not running. It is an on/off switch.

Engine coolant temperature sending unit. Is on the side of the cylinder head facing the passenger side of the car. It is the closest sensor to Temp switch B. It only has one wire going to it. It controls the temperature gauge in your car, so its signal (resistance) varies.

Engine coolant temperature sensor (ECT sensor): It is on the same face of the cylinder head facing passenger tire, but closer to the windshield. It has two wires going to it. This sends the coolant temperature to the engine computer, so the engine computer can balance the air/fuel mixture. It signal/resistance varies too.

I have the same problem with my 01 Accord V6. Now the temp gauge is maxed most of the time, been off all night get up and start car, its already maxed but runs good and cool and fans come on and shut off normally.

Anyways can you give me the same details so I can fix my Accord, as I just replaced the timing belt, water pump, thermostat, radiator and one fan.. Egr valve and cleaned the port and then this... LOL

215,000 miles and going strong.
Thanks,
Chuck

#19

08-27-2015, 04:29 AM

Joyce.Tyler541

Newest Of Newbies

Join Date: Aug 2014

Posts: 21

Quote:

Originally Posted by scrapmetaljoe

215,000 miles and going strong.
Thanks,
Chuck

Your temperature sensor wire is probably grounded out somewhere. (short-to-ground) The way temp sensors work is resistance. Less resistance=higher temp reading. So if it is grounded out then it will peg the gauge. Look at your wire to your temp sensor and make sure its hooked up correctly and inspect for damage. If you dont see anything obviously I would check for continuity next.