ECT sensor wires gone?? HELP

[archer886]

I recently purchased a 1998 4.6 5 speed mustang. The temperature gauge does not work. And there was nothing plugged into my engine coolant temperature sensor. I looked for the plug and it was nowhere to be found on the harness. I cut into the harness slightly and found two wires that had been cut and not connected to anything. I bought a new plug and new sensor. And connected the wires, but still nothing. My temperature sensor still doesn’t work and I have an engine coolant temperature sensor code still. I’ve searched forms, but I think this is somewhat of a unique problem. Any help or suggestions would be greatly appreciated.
Thanks, Austin

 

[gkomo]

What colors were the two wires that you found in the harness? May need to reference a wiring diagram to make sure those were the correct wires.

 

[Mustang5L5]

Photos of your intake manifold crossover??

Early 4.6's had two coolant sensors (for for gauge and one for ECU) and then at some point Ford switched over to a single unit that did both.

A lot of times folks buy replacement manifolds for the wrong year (like when doing a PI swap on a 96-98) that only has a single location, and they don't install the sensor for the cluster rather than drill/tap for it.

Some pics might help clarify what is going on here

 

[archer886]

What colors were the two wires that you found in the harness? May need to reference a wiring diagram to make sure those were the correct wires.

The color of the wires that I found in the harness not connected to anything are Red/white strip and yellow/orange strip. If I figure out what wires go to the ECT center straight from the PCM, would it be possible to rewire my own wires? Thanks for the reply.

 

[archer886]

Photos of your intake manifold crossover??

Early 4.6's had two coolant sensors (for for gauge and one for ECU) and then at some point Ford switched over to a single unit that did both.

A lot of times folks buy replacement manifolds for the wrong year (like when doing a PI swap on a 96-98) that only has a single location, and they don't install the sensor for the cluster rather than drill/tap for it.

Some pics might help clarify what is going on here

 

[Mustang5L5]

From that angle it does appear that is a 99+ PI intake. It has the spot for one ECT, but 96-98 used two sensors.

Here is an aftermarket 96-98 intake with the two spots highlighted. One does the cluster, and the other is for the ECU

One is a sender, and one is a switch
Part DY1144 line: MOT Motorcraft - Coolant Temperature Sensor (for ECU)
Part SW5174 Line: MOT Water Temperature Switch (for the cluster)


I believe the port on the pass side on the 96-98 mustang is for the switch for the cluster, so it will not accept an ECT sensor wired in. The wires for that sensor should be on the dfrivers side.


On the 99-04 cars there is only an ECU sensor on the pass side.