Hello there!

So the temp gauge in my truck (94 b2300) does not read properly. It will move a little after running but not much.

We connected a scan tool and read the temp sensor reading and compared it to the reading from a pyrometer taken at the temp sensor and the readings matched. I have heat (really good heat) in the truck.

What would be the next step in troubleshooting this issue? I made another post about a "thermosensor" just because I was curious as to what that part is. I will be in my electrical class tomorrow to troubleshoot this problem, just wondering what a good direction to go in would be.

Thx!
Wily

A thermosenser--in this case, your Coolant Temprature Sensor, or CTS--sends a steady amount of voltage to your ECM, varying it as your engine warms up and reaches your standard operating temprature. It will, if you go someplace and let it sit for a while, also send less voltage as you start it back up and drive it again.

The answer to your question is: There's no issue here. Your CTS is working properly, especially if you have good heat. However, if you still think there could be a malfunction in the system, have your coolant system flushed (cleaned/hot water flushing out any crud/buildup) and re-filled, and also have your radiator cap tested, to make sure the pressure on the cap is the proper pressure. Also, check and/or replace your thermostat--this sounds like it could also be a stuck open thermostat (therefore not allowing your coolant to reach proper operating temprature).

Hope this information helps.

thx for the reply. I feel there is certainly something not functioning properly. Would be possible to have decent heat and still suffer from an overcooling condition? We read the sensor and pyrometer at around 165* F. Does this seem low for a vehicle that had been running for about 20 minutes? I do question the radiator cap honestly and plan to replace that as a pre-emptive measure. Would a faulty thermostat also allow decent heat to be possible?

Cooling system has been flushed twice in the passed month due to a water pump replacement and a second replacement under shop warranty.

Thx for the feedback!
Wily

seems low.. could be the thermostat stuck open and wont let the truck warm up...

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00 Ford F-250...5.4L with some goodies, 4x4, Auto out of a 7.3 powerstroke w/ stage 2 TC , Crew Cab, Burnt orange, 35x12.5 MT Baja ATZ's on 20x10 Motometals, Pioneer Deck, Scanguage, Magnaflow exhaust, LED signal tow mirrors, and a Hidden hitch gooseneck

thermostat open temp starts at 192 and finishes at 212 (per mitchell ondemand). sounds like I'm having an overcool issue indeed. That temp was taken after running the truck. might not have been 20 minutes though. I should drive it around and check the temp afterwards. If it's low after driving then clearly I have a cap issue or a stuck thermostat.

Sorry to bring this topic back up, but this information is relevant.

I noticed that when I first got my truck that the temp needle wouldn't move very much.

Then, about a month and a half ago, my friend told me that I wasn't shifting right (I've got a manual trans). So, shifting five miles an hour HIGHER, I noticed after about 20-30 minutes of driving, the needle would be right where it should be, on the cooler side of the 'normal' word on the temp gauge.

So, if you have a stick, I would suggest driving it a little harder, that way you can see if your thermostat is actually stuck open or not. As you drive the truck harder, you'll be able to see the temp go up, and then if the thermostat is working, it should drop back down (driving highway, anyways).

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Billie, my "sparkly" blue 1992 Ranger
SPECS: 2.3 I4; Rebuilt motor at 194,263 miles; straightened driveshaft when engine was rebuilt

FIRST MODS: 2" suspension lift and rear disc brake conversion

Hi. I should have wrote back sooner. Using an ohm meter we found the temp sending unit is bad. It is reading far out of spec. 66 ohm on a normal op temp engine. Sahould have been closwe to like 25.

I Have a 96 3.0 5 speed and my temp gauge will not reach the middle and normally sits @ 1/4 or under the lil boat.. The Gauge will do what I call a lil Tweeker Twitch or move up and down very quickly off and on while driving or sitting.. its not a constaint twitch... I just bought a Temp Sender Switch but im Not sure if its the same and gos in the same place as a coolent temp sensor. My buddy told me to place a card board in front of the radiator to make the temp move and it almost got to half but there was a lot of heat under the hood
.... Can Some one help Me out Please Should I replace some thing else.

It sounds like the sensor is bad or the wire is bad. Buy the proper replacement parts. Do not put cardboard in front of the radiator, that will just make the truck overheat. Your buddy is an idiot.

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(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide

+1 to the cardboard/id-10-t error. You don;t want your truck to overheat.

This may be different for you but on my truck the sensor and SENDER are 2 separate things. The SENSOR is for the PCM and the SENDER is for the gauge. If you pull up a wiring diagram it should show you what the gauge gets its info from.

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Current: 2000 Ford Explorer XLS 4x4 Automatic 4.0L SOHC

Gone but not forgotten ~ "Ghetto Blue" my 1994 Mazda B2300 5 Speed Standard Cab 4x2.

The one with one or two wires (i forget if its one or two) is for the gauge. The one with like 4 or 5 wires is for the PCM. The scantool is reading the PCM sensor. Which is why the scantool and pyrometer are reading correct and the same. The gauge one is probably f'd up.

__________________
(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide

If that's in reference to my issue that is 100% what was going on. The sensor was fine, the sender was / is what's faulty. It has 1 wire that hooks to it. I havnt bothered fixing it yet cuz it's in a bad location to get to, Lol. I really need to get it done. Maybe next lab time, lol.

__________________
Current: 2000 Ford Explorer XLS 4x4 Automatic 4.0L SOHC

Gone but not forgotten ~ "Ghetto Blue" my 1994 Mazda B2300 5 Speed Standard Cab 4x2.

Thanks guys but the Cardboard was there just to see if the needle would move.... I called Napa auto and the guy thats been helping me told me that its for the Guage and its some where on the back of the block on the driver side...

The sending unit is located on the driver side of the block. It's a bear to find. It is below the oil sending unit. We put the truck up to access it. The sending unit threads into the block. It is hard to see even if the truck is up. it will have 1 wire coming off the top of it with an elbow like connector. the wire is black with a white tracer i think.

This is how it was on my 2.3l anyway so assuming it's at least slightly similar hopefully this helps!

Cheers,
Wily

__________________
Current: 2000 Ford Explorer XLS 4x4 Automatic 4.0L SOHC

Gone but not forgotten ~ "Ghetto Blue" my 1994 Mazda B2300 5 Speed Standard Cab 4x2.

Thank you

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where would i post for somg and computer issues