There have been many threads on this problem before, and I have read many of them. But I’m hoping someone who was having trouble in the past might have gotten some insight into how to solve this problem.

My temperature gauge is not working right. The gauge and wire have been tested by grounding the wire at the engine block. The sender (and the correct one) has been replaced using no sealant on it in order to get a good ground. Still, the gauge is not registering. After running the engine, if I turn it off, wait a few minutes until engine heat hits the maximum, then turn on the key, the gauge will move slightly but never getting up to the C. When I hook up the obd scanner and look at “live data,” I see the engine is running right at 200 degrees.

Any hints from anyone? And thanks.

 

I got one of the aftermarket gauges that taps into the upper rad hose. Like you I r&r'd the sender etc and it still didnt work. So glowshift had a special on the water temp and the oil pressure (another issue) so I got both, added a pillar gauge setup and now all is good.

 

Thanks for your reply. If I can't get this thing to register temps soon, then I'll do exactly what you suggest. Too much trouble to keep messing with it as it is.

 

not sure what year yours is, But if you are like my 2000 Ranger 4.0l, It has 2 temp sensors. 1 has a single wire off it and goes to the PCM only. the other has 2 wires off it and it goes to the PCM and temp gauge.

 

Connect your ohm meter to the sender, does it go from high resistance with engine cold to lower resistance hot ?

 

Yes, it does vary from 2700 ohms when cold to around 375 when hot. My wiring diagram for the gauge says the sender should be around 74 ohms when cold and 9.7 when hot. That is a huge difference, and I am wondering if the sender I bought is the wrong one. What is a normal hot/cold ohms reading for a Ranger sender?

 

74 ohms cold and about 10 ohms hot sounds about right. Best bet is to check with a Ford dealer parts department
They should have the right sender for a couple more bucks

 

So here is what has happened. Before going to an aftermarket gauge, I tried one more thing. I found a fitting that goes into one of the hoses to the heater and takes the threads from the temperature gauge sender. I moved the sender to the heater hose, and the gauge immediately began to work okay. Why the sender would not work in its original position in the engine I don't have a clue.

 

Faulty ground connection possibility, comes to mind. What was used to seal the sender threads to the engine block & how rusty or corroded were the threads?
How are the battery to engine, body & body to engine ground connections? All need to be clean, bright & tight.
If all that checks out, perform a wiggle test on the sender wire run, looking for signs of broken strands from mash or crimp damage & inspect its crimped wire strand to electrical connector connection for broken strands, loose crimp, or corrosion at the crimp connection.
If all that checks out, put the replacement sender on the suspect list & give it a thump & wiggle test of the wire lug contact. Just because a part is new is no guarantee its good, I've seen & heard of plenty of faulty new parts right out of the box!!!
More thoughts for consideration, let us know what you find.

 

I'm trying to figure out you are grounding a single wire temp gauge sender thru a rubber hose???????????????????
But whatever you did i'm glad the gauge is working

 

The T fitting that I inserted into the heater hose to hold the temp. gauge sender is metal. I ran a ground wire from the firewall to the fitting and attached it to with a stainless pipe clamp. You're right in that the sender is a one wire only and would not work without the ground.

 

So as soon as you gave the sender a proper ground with your new setup the gauge began working, but it wouldn't ground thru the block. Go figure
The oil pressure sender is also a single wire & also grounds thru the block. How the oil pressure gauge can be working properly but the temp gauge didn't is a real head scratcher.
Main thing is you now have a working temp gauge, congrats on the fix.

 

Yes, it seems to be some of these things that should be "simple" that can drive you the craziest. So, the problem is solved in that I have a working temp gauge, but the mystery remains.