Coolant temp senders

[CharlieZ]

Wanted to post that the radiator fan switch and coolant temp gauge sensor from Advanced don't play in my 90L 5 spd w/tach cluster.

Picture shows difference. The Advance part for the fan switch looks like the OEM temp gauge sensor but it isn't.
The Advance fan switch operates just like the OEM in that it is a temperature sensitive on-off switch that opens when coolant temp reaches 207°. The coolant temp gauge varies its resistance with change in coolant temp. Advance P/Ns: Radiator fan switch = TFS525. Coolant temp gauge sensor = W5000.

Other than JY, does anyone have ideas? Did all years of Festivas have same size parts & threads with same connector types?

[bhazard]

The one with the spade connection is the fan switch. The pole connection is the gauge sender. The two pin one is the ECT sensor for the ECU.

[bravekozak]

Green Sales (obsolete Ford Festiva parts) or Four Green (Kia Pride parts).
In both cases, you will need to know the part numbers.

Here is the part number for the temp sender.
He does not want the two pin switch.

[CharlieZ]

The one with the spade connection is the fan switch. The pole connection is the gauge sender. The two pin one is the ECT sensor for the ECU.

I have no reason to doubt what you say but per the schematic, by continuity check, what you're saying is just the opposite of what I find.

The small sensor, with bullet connector, is screwed into the block definitely is the fan switch. In the shop manual, C-125, GN/Y wire to cooling fan relay C-124.

The larger sensor, with the spade connector, is screwed into the coolant outlet housing, is the temp gauge sending unit. In the shop manual, C-131, Y/W wire to Cluster C-210..

I haven't messed with the ECT sensor but I see that it is has two pin connector.

Both are shot so I can't use the boil-in-water test on the senders.

I'm going back out to the shed and check it now.... again

Darn it! I may come back with a egg on my face.

[crazyrog17]

The switch on the coolant outlet housing is the fanswitch, the one in the block is the temp sender.

Try grouding the terminal for the switch on the coolant outlet housing and the fan will kick on (unless it's the other way around in which case it will turn off).

[zoe60]

The temp. sender units come in two different thread sizes. Beware of that. I can't remember exactly, but newer engines take a different size.

[CharlieZ]

Just got back from the shed.

bhazard
The wire with the bullet connector is Y/W
The wire to the spade connector is GR/Y
I find a splice tied into the wire conduit on the bullet connector wire and an non original wire routing the bullet connector to the fan relay. Oh me! Something is screwed-up. Will look farther tomorrow. Thanks

Crazyrog17, if you have a shop manual, look at page 151-1 for the fan switch C-125 along the bottom margin. Then look at pg. 151-2 along the right margin for the coolant temp sensor C-131. I believe there is a mix up in where the lines are pointing. Like just opposite of what really should be. No wonder I'm screwed-up. Well that's not the only reason.

bravekozak
Thanks for the resources.

[Pu241]

I concur with both Bhazard and Crazyrog17!

I know for a fact the bullet connector is for the instrument cluster gage, replaced with used OEM many times.

Never replaced either the fan switch or ECM temp sender but they are as has been described.

[CharlieZ]

That's what happens when I put stuff off. After a leak in the heater core, I've been running the heater by-passed with a hose, no pressure cap, and manually switching the fan "when I thought I needed it." With $3.65 gas, summer coming, and more driving to g'kids baseball games, I thought I better get busy.

I called Advance to hold the fan switch I returned. Looks like the gauge sensor will take a JY run.

Thanks to all who helped.

[bravekozak]

Green Sales shows three temp senders in stock.
E8BZ10884A

[CharlieZ]

Got it going OK. The mix-up was partially due to my shop manual. Then throw in the ECT switch thought to be the gauge sensor, then the spliced wire, etc. I went back to Advanced and got the returned $45 fan switch then to AutoZone for the temp gauge sending unit, P/N TU75 for $17. I returned the ECT $19 switch. I'll "refix" the wiring and all should be a go.
BTW, my engine has 1/4 X 27 NPTF thread on the gauge sensor.
Thanks again for all the input.

[CharlieZ]

I need to revive this older thread with related questions..

Does anyone know the designed resistance value of the OEM coolant temp gauge sensor?

I'm having some gauge issues, I disconnect the bullet connector and connected a high quality Triplett analog ohmmeter to the sensor terminal. At cold (ambient temp 40 deg F the resistance measures 1200 ohms. Letting the engine warm up to the point where the fan kicked in, the resistance was measuring 50 ohms.
I had no way set-up to measure the actual coolant temperature. As the fan ran, and the coolant cooled, the resistance rose to 60 ohms, at which point the fan shut off.

I don't have the fan switch specs either.

The factory gauge in the dash is definitely crapped out.

So, I looked at an Equus brand electrical gauge "kit" at O'Reilly. There was no sensor in the package and nothing in the instruction hinted to one being in the kit or a specific sensor to use with this gauge. The salesguy didn't know if the gauge was designed for stock sensors or if one was missing from the package. He only had one in stock. No info on the Equus web site either. Hard to believe that all cars would have the same resistance value in their sensors.

Any clues on the OEM sensor resistance, fan switch on-off specs, and/or the correct sensor for after market "universal" temp gauge would be much appreciated.

[bravekozak]

coolant below opening temp, temperature 97C (rising), resistance 10,000 ohms or greater.

coolant above, temperature 97C, resistance 0-5 ohms.

coolant below closing temp, temperature 90C (falling), resistance 10,000 ohms or greater.

The shop manual temperatures are in Celsius.
Water boils at 100C

[CharlieZ]

coolant below opening temp, temperature 97C (rising), resistance 10,000 ohms or greater.

coolant above, temperature 97C, resistance 0-5 ohms.

coolant below closing temp, temperature 90C (falling), resistance 10,000 ohms or greater.

The shop manual temperatures are in Celsius.
Water boils at 100C

Thanks for the info. For the life of me I don't see this info in the Shop Manual. Section 33-25 deals with the coolant temp system and diagnosis.
Very possible we have different manuals. Mine is the Ford Parts & Service Division, Festiva Car Shop Manual- Body/Chassis/Electrical/Powertrain.
Base on your info. My sensor is out of the ball park. The resistance cold is less than spec by a magnitude of nearly 10 and the hot resistance doesn't see zero ohms. I'm off to the parts store to get a new one to test.

[CharlieZ]

Just for ref data, I measured resistance value of two coolant temp sensors. Cold about 40deg F, in range of 1200 to 1250 ohms. In a pan of boiling water, 35 to 40 ohms. The value hopped around a bit at the hot, or low end.