Where is it?
The coolant temp gauge on my 93 Splash has never more than struggled off the cold mark even in hot weather, thermostat is new and have replaced the sender unit in the by-pass hose coming off the water pump twice to no avail, even changed the gauge in the inst. cluster with no effect.
There must be a sender unit for the gauge itself, as it seems the one in the by-pass hose is the ECT for the computer.

But where?

 

I believe you may be correct, Ken...........but seeing in there would require miniaturizing myself to about 3" high to investigate.

 

Temp guage is usually in the head dave.

 

Here is a question along the same lines but involving the 7.3 and maybe demonstrating my extensive knowledge and understanding of how things work.
My temp gauge does about the same thing as what Dave is describing. Just barely gets into the "normal" operating range and stays at the same place no matter what type of driving terrain, engine load or outside ambient temps. I've been told in the past that the temp gauge is really nothing more than a glorified "dummy light". In other words it stays right where it is unless it gets too hot then it will peg out at the top. No in between. So, I've just accepted that and never questioned it, until now when I saw Dave's post. Guess now is just as good a time as any to check and see if I have a gauge or a "dummy light" disguised as a gauge. If it is a "real gauge" I would guess I have the same problem as Dave does.
I put a Scan Gauge II in #ad
which plugs directly into the OBD II port. My 96 computer is not fully OBD II compliant and I can't get about 98% of the Scan Gauges functions to work, but I can get coolant temp, rpm's, oil tem, voltage as well as a couple of other minor not so important things.

 

dave's is a different situation than yours Jim.
Temerature guage on your 7.3 is an idiot light, as is the oil light.
I can't help with the temp, but here is the cure for the oil pressure....
http://www.rowand.net/Shop/Tech/FordOilPressureGaugeFix.htm

 

Thanks guys. Pretty much what I had heard in the past. Interesting article Charlie. I'm afraid my 96 sits in that "90's" group of solid "dummy gauge" state programmed right into it. Had the instrument cluster out a couple of years ago replacing all of the dash lights. One big film type printed circuit board.
What's just as interesting is that while I can get the Scan Gauge II programmed to give me Engine Oil Temp., I can't get it to give me Transmission Temp or Engine Oil Pressure. transmission Temp has been resolved but I guess if I want to see actual Oil Pressure I'll have to get another post market gauge like I did for the transmission temp. #ad
I shall now return you to your regularly scheduled program and surrender myself to the air marshals for the hijacking.

 

Mfg's don't WANT you to know how low oil pressure drops to on a hot day at idle, in drive...................people might get upset.

 

I have always wondered how to fix the gauge in my Vic. I knew it was an idiot gauge because of the way it acted. Time to go to the local junk yard and see if they have a Vic cluster out so I can check and see if the resistor is a ready fix.

 

I have searched all over the motor with inspection mirrors and from underneath, I can find no other sender unit besides the oil press. sender on the back of the head and the ECM coolant temp sender in the by-pass hose by the water pump..............I am beginning to believe this one controls the gauge too, and since it is literally hanging out in space in clear air-flow, it's never going to show any temp on the gauge.

 

According to AutoZone Dave, "Under hood, center, front engine area, below valve cover, mounted in water outlet" but they didn't show any pictures.
Looking up radiator hoses for the 97 Merc. Wow, they want a gold mine and your first born for one of those!