Water temp and overheat sensor location?

[Fiat88]

Finding conflicting information regarding the two sensors proper location. Is this right?

The water temperature sending unit with the green/white wire goes in the hole closest to the timing belt and the overheat sensor which pegs the needle goes towards the firewall and has grey/black wire? Help! Thx.

[124JOE]

i thought the over heat sencer was on the radiator
it must be the fan switch

[manoa matt]

As long as the correct wire is connected to the correct sensor, I don't think it matters as the threads are the same and the water port area under the sensors is connected.

[Fiat88]

As long as the correct wire is connected to the correct sensor, I don't think it matters as the threads are the same and the water port area under the sensors is connected.

I thought maybe one part would be hotter then the other.

[WYSpider]

Haynes, pg. 59, section 13.2 (1968-1978): "the sender units for the gauge and warning light are screwed into the top of the cylinder head - between the spark plugs. The forward sender unit operates the warning light."

[courtenay]

Can someone explain what the "pegging the needle" sensor actually does? I've disconnected mine - on my '80 Fi, it's the one closest to the radiator. When it was connected, the needle continually headed towards the red zone. Disconnected, the needle sits where it should - around 190 - 195 - with the cooling system working as it should.

[Fiat88]

Haynes, pg. 59, section 13.2 (1968-1978): "the sender units for the gauge and warning light are screwed into the top of the cylinder head - between the spark plugs. The forward sender unit operates the warning light."

Thanks!

[Fiatmonkey]

Just want to throw in some old truth from Fiat. Originally even Fiat put these in backwards on the cylinder head. Not a lot of quality control back then. If they worked they didn't care what whole Tony put it in.

[bradartigue]

On most cars the wire for one is shorter than the other; hence you install the things where the wire will reach.

The function of the pegger is to..peg the needle. To alarm you into doing something about your overheating car. They do fail, for whatever reason they seem to fail more than the sweeping one. You test your system with the pegged one disconnected, then once you verify that everything is working (gauge, fan, thermostat, etc.) you hook it up. If it does nutty stuff you replace it.

[Fiat88]

I did replace them with new ones. The wires are connected to the right ones. The reason I'm asking is that my fan wasn't going on but the lower rad was hot. The needle crept past 210, showed it to a mechanic and he said it had something to do with my temp senders,something to do with polarity. When he was troubleshooting it, the fans went on and the temp stabalized. He told me to switch the wires, but when I checked the wiring diagram everything looks connected right.

Today I installed Marks procomp adjustable sensor, will test it out tomorrow.

[manoa matt]

"my fan wasn't going on but the lower rad was hot."

Suspect a bad fan switch or bad ground connection at the "bottle cap" ground pod on the DS inner fender. Or an air bubble in the system just below the thermostat in the lower rad hose.