Over heating and gage shows Normal?

[RangerRick]

The first time I posted on this site (great site), I was all butt hurt because of a fuel pump that went about a week after buying the truck.
Now I'm stuck with a problem I can't find enough info on.

My truck has 75k miles, 2wd, auto, it goes to work and back and thats it. The drive to work is about 6-7 miles one way and the truck will over heat in that time period.
I initially thought the thermostat was faulty and spent the mega millions required to buy one (Thank you Ford!) only to find out it's not the problem. The engine heats up fine, but the lower radiator hose is always cold. This means new or not the thermostat is not opening.
Now because Ford engineered this wonderful POS for a thermostat to require some type of electrical necessity you cant test the thermostat in hot water to see if it will open, it must have some type of electrical signal. Thus my quandary.
This problem sets off a CEL and I can't get plates because....I can't pass emissions with a CEL.
All because of a simple thermostat and Fords wonderful engineering!

Everything has been tested, no head gasket leaks, no burning of coolant, no coolant leaks, just overheating due to the thermostat or electronics.

Is there an electrical schematic for 2002-2xxx Rangers I can browse. Ive spent a small fortune diagnosing this, less than the stealer wanted ($500, cause they want to replace the thermostat ($207) the rest is labor, and it takes all of 15 minutes to replace). From that its painfully obvious the stealer has no clue whats wrong.

Hope you had a good New Year.

Edit:
CEL is P1432
Thermostat Heater Control Circuit Failure

 

[xplorercrazy]

The thermostat in this truck still opens like a normal thermostat based on coolant temperature. The electrical part is for a built in heater which is so that it will start to open at a lower coolant temperature than normal when the PCM decides that it is necessary.

 

[xplorercrazy]

Also I am guessing that your heater does not work very well either?

 

[rwenzing]

P1432 is a simple circuit check code indicating that the voltage at the PCM is out of spec on either the low or the high limit. This often means a simple electrical fault like a short to ground or an open.

If you eliminate the PCM (rarely fails) and the electronic thermostat (already replaced), then all you are left with is 2 wires and a fuse.

Fuse 41 (20A) in the underhood Battery Junction Box

Light blue/orange wire from Fuse 41 to the t-stat

Dark blue wire from the t-stat to the PCM

 

[RangerRick]

The thermostat in this truck still opens like a normal thermostat based on coolant temperature. The electrical part is for a built in heater which is so that it will start to open at a lower coolant temperature than normal when the PCM decides that it is necessary.

Also I am guessing that your heater does not work very well either?

The thermostat is factory set to 220°f, the thermistor allow it to be electronically controlled up to 50°f less, typically operating around 192°f. If the thermistor fails the engine temp will run about 220°f plus and higher if the thermostat fails too.

My heater works great!? The only thing not working is the thermostat assembly, coolant flows through out the system except to and from the thermostat assembly. Lower radiator hose at best will be slightly warmer than ambient air temp. Upper hose will burn you within seconds.

P1432 is a simple circuit check code indicating that the voltage at the PCM is out of spec on either the low or the high limit. This often means a simple electrical fault like a short to ground or an open.

If you eliminate the PCM (rarely fails) and the electronic thermostat (already replaced), then all you are left with is 2 wires and a fuse.

Fuse 41 (20A) in the underhood Battery Junction Box

Light blue/orange wire from Fuse 41 to the t-stat

Dark blue wire from the t-stat to the PCM

I actually started testing the electrical lines, simple system. I hooked up an LED to the positive side (DkBlue) and the light stays on all the time. I assumed it should have been on and off depending on use. This means the positive side is good to the plug.

Im going to swap them around and put it on the ground side and then to a positive side and see if it lights up at all.

Thanks for the info.

 

[xplorercrazy]

I can send you a PDF file that has the test procedure for code P1432 as well as the wiring diagram for the thermostat if you would like it.

 

[RangerRick]

That would be cool. Real cool.

 

[Ronald Hribar]

may be all wet

But am thinking that you may have an air spot in your cooling sytem
Did you refill or replace your coolant?
The best way is to take a heater hose off and fill till coolant comes out the top of radiator

Maynot be the answer to your problem but seems like you covered everything else

 

[RangerRick]

Ive done that. Im drawing straws anymore.
I think its air in the block that I cant purge because the thermostat isnt opening.
This weekend I am adding a manual bypass from the thermostat to heater core line to the lower radiator hose in hopes to bleed out any air.

 

[4.0L2WD]

replace your coolant temp sensor located on top of the thermostat housing.

 

[RangerRick]

You cant, its built into the thermostat assembly. It is one of the reason the thermostat assembly costs from $134-$257. Depending on where you buy it from. Now that I think about it, thats only the thermistor (heater device)
http://www.rs-productions.com/Images/mirt1157.jpg

And then they don't work anyhow.
I had to create a bypass to keep the engine from over heating, it has over heated so many times I now have to replace the coolant recovery/fill tank and cap because the tank is disintegrating (basically melting from steam).
There goes another $83.

Has anyone tried to use the 2006-present thermostat assembly ($40)? How can I bypass the thermistor without a CEL?

 

[4.0L2WD]

Actually you are wrong. There are (2) sensors that seet into the housing. They either screw in or are held in with a c-clip.

Rockauto or monument auto parts sell the motorcraft housing for under $70.

I have replaced 5 t-stat housings, sensors, hoses, I think i would know. Plus their is a 30 page thread on this board about the t-stat housings being a ***** to install.

good luck

 

[rwenzing]

Actually you are wrong. There are (2) sensors that seet into the housing. They either screw in or are held in with a c-clip.

Actually, since the OP is talking about a 2002 2.3L Ranger, you are wrong. Compared to your 4.0L, it is a very different arrangement, mechanically and electrically.

 

[waskly]

i think in 10 years i have worked on 3 rangers in my life, but as others have stated above, fuse, wiring, or pcm control. the pcm will ground the circuit, and see a drop of voltage since the resistor will work then on the thermostat. so i would check that.

 

[RangerRick]

Actually you are wrong. There are (2) sensors that seet into the housing. They either screw in or are held in with a c-clip.

Rockauto or monument auto parts sell the motorcraft housing for under $70.

I have replaced 5 t-stat housings, sensors, hoses, I think i would know. Plus their is a 30 page thread on this board about the t-stat housings being a ***** to install.

good luck

Not dissing you, but I can R&R a t-stat on a 2.3 in about 10 min flat. Done it 4 times now. First time took all of 30 minutes. 4 bolts, one plug, two coolant hoses.

I bought the last assembly from rockauto for $134 shipped. That is the cheapest I found any where.

Back on topic, I think the temperature gage in the dash is reading wrong, how else could it overheat and only show normal?
The temperature is read from the head (havent found the exact location, just read about it). There are three total sensors, Head, Oil and thermistor (not to be confused with thermostat).
With the bypass I created I now can feel very warm temperatures in the lower radiator hose, which I could not before with a new thermostat.

 

[Yoshi Johnson]

The first time I posted on this site (great site), I was all butt hurt because of a fuel pump that went about a week after buying the truck.
Now I'm stuck with a problem I can't find enough info on.

My truck has 75k miles, 2wd, auto, it goes to work and back and thats it. The drive to work is about 6-7 miles one way and the truck will over heat in that time period.
I initially thought the thermostat was faulty and spent the mega millions required to buy one (Thank you Ford!) only to find out it's not the problem. The engine heats up fine, but the lower radiator hose is always cold. This means new or not the thermostat is not opening.
Now because Ford engineered this wonderful POS for a thermostat to require some type of electrical necessity you cant test the thermostat in hot water to see if it will open, it must have some type of electrical signal. Thus my quandary.
This problem sets off a CEL and I can't get plates because....I can't pass emissions with a CEL.
All because of a simple thermostat and Fords wonderful engineering!

Everything has been tested, no head gasket leaks, no burning of coolant, no coolant leaks, just overheating due to the thermostat or electronics.

Is there an electrical schematic for 2002-2xxx Rangers I can browse. Ive spent a small fortune diagnosing this, less than the stealer wanted ($500, cause they want to replace the thermostat ($207) the rest is labor, and it takes all of 15 minutes to replace). From that its painfully obvious the stealer has no clue whats wrong.

Hope you had a good New Year.

Edit:
CEL is P1432
Thermostat Heater Control Circuit Failure

Hi Rick,
My husband also replaced the thermostat on his 2002 ford ranger and is getting the same code. Were you able to find out what the problem was? We really can't afford a new vehicle.