NicHoza

Hello everyone. I am trying to fix the water temperature sensor (getting a diagnostic code #4). Green two-prong plug.

I quickly found part of the problem. There is a two-wire connector on the passenger side of the engine which is unplugged. The connector is green and matches the connector that plugs into the temperature sensor. One of the two wires (black?) measures zero ohms of resistance between it and one of the water temp connector wires. The other (white?) is not connected directly to the temp sensor connector -- it has a resistance of 3kohms or something. In the picture below I circled this connector in green.

I also found a one-wire cable that was cut (circled in orange).

What I was wondering is if anyone knows what this connector should be plugged into. Does anyone know what the other white wire in the connector is?

Thanks!

Photo:

snobdds

Do you have AC? All of trucks that did not come with AC had a connector that was grey and it just hangs loosely there. However, it looks kind of green there, so it must go on the tempature sensor on the front of the intake manifold.

The orange wire is a ground wire. It usually gets grounded to the lower intake (the right most lower intake bolt in your picture) for the fuel injectors. However, It is usually part of the wiring harness and should be wrapped in a black sheeting with a yellow line down the side.

It looks like you have some hack wiring going on there. I would try to find out what is going on with your wireing harness. Post some more photos, I know a 22re wiring harness like the back of my hand...

NicHoza

I do not have AC. Perhaps the gray connector you speak of is the one in the blue circle in the photo below?

The orange circle was supposed to be around the gray tube. Not really fair to ask what that is since it is cut off and you can't even see the color of the wire inside. I circled it in orange again in the new photo below.

In this new photo I show the green connector I am unsure about (upper left) and the green connector that goes to the temperature sensor (lower right). Testing with a multimeter showed that there is a shared wire at these connectors (each connector has two wires). However, I guess this could just be ground or a common +5V or something like that. Not necessarily closely related connectors.

While we're at it, what is the thing in the pink circle? Hmmmmm.... could the orange-circle thing and the pink-circle thing go together? Haven't even looked at those closely.

Thanks!

snobdds

1. Lower Green conector needs to go into the thermo temp sensor in the front of the intake manifold.

2. Pink is your dash pot filter.

3. The blue circle connector in not the AC one I mentioned earlier. It looks a lot to me like the conector for your starter.

The upper green conector and the vacumme hose I can't see very well. Try getting those two in a picture better.

NicHoza

These are the two shown in the original picture. It isn't actually a vacuum hose -- there is an electrical wire in there.

snobdds

That red looking wire is not stock. Someone must have added an extra ground at some point.

That other connector almost looks like a fuel injector connector. Do you have all your fuel injectors hooked up?

NicHoza

Sorry, I wasn't trying to circle that red/orange ground wire. I was trying to circle the gray tube thing next to it, which has a wire inside it which you can't even see. Not too helpful (on my part) for identifying it.

As far as I know all my fuel injectors are hooked up. Wouldn't I notice if they weren't? Runs fine. I will check it out though.

snobdds

Then your fuel injectors are fine. Theres not much over there for that type of connector, maybe it is for the AC, but mine is grey. It looks kind of green in that picture, but it may just be the grime. What color is the connector exactly...

As far as the other wire with a sleeve on it...that may be your old ground wire and that may explain why someone put that new ground on there.

NicHoza

Yep, it's green. Looks the same as the water temp sensor connector in color.

NicHoza

Yup you called that one. Tried to start the truck and got nothing. Must've unplugged it by accident when I was messing around down there.

Still trying to figure out why I'm getting the #4 diagnostic code. Going to check continuity from the water temp sensor plug to the ECU. I guess maybe I just have a bad sensor? We'll see. Hopefully. Thanks again for help!

NicHoza

Hm.. there is continuity to the ECU and it is measuring 2.3 kiloohms. All seems well. Not sure why my dash gauge doesn't work or why I'm getting diagnostic code #4...

snobdds

The sender for your temp gage is on the upper intake manifold dead center of the head. It is usually a spade connector type fitting. Remember, the sensor at the front of the intake manifold sends a signal to your ECU only. It has nothing to do with what your temp gage is reading.

I have to be honest, I have no idea what else that extra green sensor in your first picture goes to.

NicHoza

Alright.. what is this picture? You can see the sensor I took out right above the thermostat and the connector that goes to it.

Note: Back and below this there is another temperature sensor which goes to my aftermarket gauge.

Also note: I tested this sensor and it is an open circuit. I tried running it under hot water, and it's still just an open circuit. I'm guessing THIS is why my dash gauge isn't working?

snobdds

That is a tempature sensor, I know one furter back on the intake manifold is for your gague. Do you have an automatic transmission...? I know the overdrive on an automatic is ran off of coolant tempature. It will not allow the OD to kick in until the motor is at a predefined tempature.

Also those thermostat neck came on turbo trucks...tell a little bit more about your truck i.e auto, turbo, manuel, etc...

NicHoza

Okay. Here are two temperature sensors A and B. Sensor A goes to my aftermarket gauge. Is this where the sensor is that normally goes to the dash gauge?

Sensor B doesn't seem to work. I measured with an ohmmeter and it is a short circuit, even under hot water.

Also interesting: I connected the wire going to Sensor B to ground through a 100 ohm resistor (with the key in the ignition in the on position), and every time I did this there was a clicking noise from somewhere inside the engine it sounded like. Any ideas what that could be?

NicHoza

Also... I was confused about that wire that I said went to the starter motor. Turns out there is another one, and the starter one just happened to be unplugged....... here is another picture. Colors correspond to previous pictures (I took the "sheath" off the orange-circled wire):

NicHoza

Regarding the sensor above the thermostat (labeled sensor "B" above).. one person says

"The temp sender for the gauge is on the side of the head, not on top of the t-stat housing. That one is for a hot start feature that the ECU uses."

Someone else says the sensor "above the thermostat is for the AC".

A third possibility presented by this diagram (http://www.well.com/~mosk/Images/22RTE_EFI.pdf) is that it is the "Water Thermo S/W (4WD)" whatever that is. Has the right color wire. Some sort of a switch.

These can't all be right. And neither one is what I'm looking for. Hm. Not sure exactly what I am looking for.

UPDATE: found the wire that goes to the temp gauge. Blue connector (not pictured). Oh also my truck is a manual non-turbo, no AC.

NicHoza

Looks like sensor B is the 4WD water thermo switch (I checked and the connector has continuity with pin 16 on the ECU's 18-pin connector). Anyone know what this is for? Why do only 4WD vehicles have it?

Justmonkeywrenchit

That green connector I believe should go to a VSV valve, on my pickup it's blue, and should have a couple vac. lines running from it. Did you happen to figure out what the problem was? Mine's doing the same thing...

NicHoza

Nope. Never figured anything out.