Hi guys!
I just bought a ´89 F150 with a 4,9l and 5-speed manual. Water temp gauge does not work,so i thought that maybe the sending unit or wiring is bad. So,where is the sending unit located? Or,does it have TWO sending units? I just read somewhere that the other one is for computer only?

BTW,What would be the best shop/repair manual to buy?

Thanks,Tommi

 

I like Hayes manuals, they have pretty good details and can be found at just about any parts store for $20 to $50 depending on what info is all in it.

 

I'm pretty sure that you have 2 sending units(1 for the gauge and 1 for the computer) The sensor for the computer is called the ECT(Engine Coolant Temp Sensor) The sensor for the gauge is located to the right of the distributer on my 302. Not sure if its in the same spot for you but its worth a look.

 

It is probably on your intake manifold twards the front, most of them look kinda like a spark plug with a wire attaced to the top of them.

 

Jeeze i have that same engine, i know theres a sending unit near the oil filter, but i think that one is for the oil, it should specify in the haynes manual.

 

The ECT sensor will be in a tee in the same cooling circuit with the heater core so that it can monitor coolant temperature as the engine warms up. That signal is used by the EEC to control fuel/air mix, and several other parameters. The temperature sending unit for the gauge is for ENGINE temperature, not COOLANT temperature, despite the fact it's stuck in a coolant passage. If everything is going well, both are the same. If not, well, you know the story. I'm not sure on the I6, but I don't think coolant goes through the intake. This means your gauge sending unit will probably be on the head somewhere. Your problem sends up electrical issue flags to me, though. If both temp and and oil pressure aren't working, they're on the same electrical circuit, and share an IVR (instrument voltage regulator). I'm not real sure, but I think on the older models, the fuel gauge had it's own IVR and the Oil Pressure and Temp meter shared one. This is because some vehicles were equipped with switches and idiot lights, and others had sending units and gauges. The IVR will be located on the back of the instrument cluster. These are a known weak spot on older vehicles. I have an '86 T-Bird. When the IVR went on it, I found my self chasing high temperature problems that didn't exist, and ran out of fuel twice because the fuel gauge wasn't reading right. A dealership finished that cluster off by connecting the battery backward and frying the digital odo/speedo, the original AM/FM/Cassette, and the alternator. But, of course they denied any responsibility. My only proof was that all were working when I drove the car in there for a new engine, with ZZTop blasting from one of the local radio stations. Somehow, my alternator went bad while it was sitting in their shop for 3 weeks with no engine in the car. Musta been aliens.

 

Oil pressure gauge works ok and other gauges as well,its just water temp which dont work. I´ll check if i can find the sending unit and if the wiring is ok.

Thanks guys.


Tommi

 

Gauge still not working.I found the sending unit,it was at back of the block,under intake manifold,i took off the wire connector and put it back on,just to find out if it was corroded or something.Well,it wasn´t and now i dont know what to do?

Any advices?
Or should i just buy A-pillar gauge pod and aftermarket temp gauge from summit?

Tommi

 

Ground the sender wire and the temp gauge should move. If it doesn't it's the gauge or the wiring, if it does then it's the sender. Do a continuity test on the wire, if that's ok change the gauge.

 

Thanks for advise dudeintruck.
I will ground the sender wire and see what it does.
Sorry,i dont know what is "continuity test"?