unplug the TW sensor and see if that helps,, it will kick a code ( 6 ) but you can clear it afterward ..

 

What the heck is the sensor beside the tw sensor? I tested both of the sensors on the thermostat housing. The tw sensor showed a little high on ohms, but it wasn't a Honda approved test either. The sensor next to it on the other hand never showed anything but an open circuit. I tried it on the lowest setting, highest setting and everything in between with no change. I even warmed the engine and retested with absolutely no change. I can't find any mention of it in the shop manual or chilton book.

 

I'm not very familiar with an 86, but that could be the cooling fan sensor.

It remains open and only closes past a certain temperature. Once closed the fans turn on to help cool the engine. Check out the cooling fan troubleshooting part of the shop manual. If that is the cooling fan sensor, you could jump the plug and see if the cooling fans come on. I would NOT do this if you are not absolutely certain that this is the cooling fan sensor.

 

Good point. I know the secondary fan sensor is mounted on the bottom of the radiator but I don't know where the other is.

 

Can you backprobe the sensor connector or is there another connector attached to this wiring (pobably not) further away from the sensor, only one wire should be 12 volts, when the fan kicks on then both should be powered. IF this is the coolant sensor 'A'. If the one in the radiator is 'A' then this one may not come on at all if it is 'B', its a higher temp. Sorry I did not look it up, its way past bed time and I have done a couple hundred forum posts tonight.

I feel confident that shorting it will be ok, it should be a thermoswitch. It does have two wires, correct.

Can you post pics?

 

Allright. Went to junkyard and got another. I put it in. My car seems to start a little better, nothing like it should. I then warmed up my car and waited for the fans to kick on. Both fans came on at once. I thought one ran whenever the engine was warm. The thing next to the coolant temperature sensor is definitely another temperature sensor. Despite both fans running at the same time the engine stayed relatively cool for just circulating antifreeze. It is impossible that the sensor I replaced controls the fans. The sensor out of my car shows an open circuit all the time while the one I put in shows that there is a circuit. The one on the left is the unknown sensor. The one on the right is the TW sensor.

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I have still been too lazy to look it up yet, but lets assume you have two temp switches for the fans, switch A turns on the radiator fan, switch B turns on the condensor fan if the engine gets too hot with only one fan on, lets say 210F, you may have what several Hondas have, a Fan controller and it may turn on both fans at 210F, these are only guesses at this point, have you been able to do any research on your fan circuits. Just answer back anything silly and I will see a new email and I promise to look it all up for you later, my memory is bad and I am out the door to pick up my kid right now. Happy Thanksgiving.

Can you please post a pic of the housing where these bad boys are screwed into.

 

I thought I had two temp sensors for the fans also. When I warmed up my engine to check and make sure both were working they came on at the same time and shut off at the same time. Also, the last pic is of the two temp sensors on the thermostat housing. The one on the left I have no idea. The one on the right is the tw (coolant temperature) sensor. When I unplug the tw sensor the engine starts about the same. I don't think it runs the same however. Both of the sensors look alike despite size difference and both have two wires. Also, I went through the book and checked out both fans. One of them shows up in the ac section and the other in cooling. I could still only find one sensor.


Is loosening up my intake manifold to check for a leaky injector a good or bad idea?

 

On your older '86 model, the Cooling Fan switch, Blue wire is power and Black wire in ground. The Cooling Fan Blue wire is the ground side control for the coil inside the Cooling Fan Relay. The power for the Relay is a Black / Yellow wire going to Fuse #15. The Cooling Fan Relay Switch gets its power from several places depending on the scenario. Fuse #9, #21, #22 and through the ignition switch during a key on scenario. When the coil is energized and the Relay Switch contacts, BOTH fans are powered on your car. The Fans Blue / Black wire is power and the Black wire is ground. I will say the Cooling Fan Switch should have 12 volts on one wire with the connector disconnected.

Reading about the TW (ECT) sensor, it is saying the wires at the sensor are Yellow / Green and Green / White wires and with the sensor disconnected, one wire should have 5 volts. This is a typical 5 volts from the ECU for most sensors that give info the the ECU.

It appears that the switch in on the bottom EDIT: OR SIDE of the radiator, for the fans, it also appears that there are both, a Cooling Fan Relay and a Condensor Fan Relay in the Relay Box under the hood in positions 2 & 4 or 4 relays, position 3 may be empty. The info above stated only one relay for both fans????

Some of this info may be corrupt, its from the same section of MOD???

What do you think of this info and can you post some close up pics showing wire colors please, I do not see a picture in my software about the sensors that you were playing with.

 

I've got pics of them. The one with the white top is the unknown. The one with the green top is the tw sensor.


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