1997 wiring problems
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Joined: Sep 2014
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1997 wiring problems
Hi Everyone!
I have a 1997 F150 that has a 5.4l in it. When I purchased the truck for $300, the motor was bad and there was some body damage. The body damage was mostly on the panel behind the drivers side door.
I have since fixed most of the body damage and have repainted the repair areas.
I put in a take out motor from a 2000 F150. I opted to use the engine wiring harness from the 2000 engine because the wiring harness from the 97 was in bad shape. That caused some problems like the O2 sensors didn't have power and my IAT didn't work and caused a CEL. I moved some wires around on the wiring connector and fixed those problems.
The problem that I haven't been able to fix is the Coolant Temp Gauge doesn't work. My first thought was the sending unit. It Ohms out good(and Ive replaced it with a new one which also Ohms out good). When I put a scanner on the truck, the scanner is showing the engine temperature. I also checked the wiring on the connector for the ECT and its pinned the same as the old harness.
I have replaced the instrument cluster with a used from another 1997 f150 and that doest change the outcome either.
I was searching on this forum yesterday, and found an old post about GEM's. I was wondering if someone could elaborate on how that might affect the Temp Gauge and or if someone had a readable wiring diagram for the instrument cluster. Also is there a pin problem on the newer engine wiring harness that I haven't caught yet that may be giving me problems still?
Any help would be greatly appreciated.
Thanks,
Perry
I have a 1997 F150 that has a 5.4l in it. When I purchased the truck for $300, the motor was bad and there was some body damage. The body damage was mostly on the panel behind the drivers side door.
I have since fixed most of the body damage and have repainted the repair areas.
I put in a take out motor from a 2000 F150. I opted to use the engine wiring harness from the 2000 engine because the wiring harness from the 97 was in bad shape. That caused some problems like the O2 sensors didn't have power and my IAT didn't work and caused a CEL. I moved some wires around on the wiring connector and fixed those problems.
The problem that I haven't been able to fix is the Coolant Temp Gauge doesn't work. My first thought was the sending unit. It Ohms out good(and Ive replaced it with a new one which also Ohms out good). When I put a scanner on the truck, the scanner is showing the engine temperature. I also checked the wiring on the connector for the ECT and its pinned the same as the old harness.
I have replaced the instrument cluster with a used from another 1997 f150 and that doest change the outcome either.
I was searching on this forum yesterday, and found an old post about GEM's. I was wondering if someone could elaborate on how that might affect the Temp Gauge and or if someone had a readable wiring diagram for the instrument cluster. Also is there a pin problem on the newer engine wiring harness that I haven't caught yet that may be giving me problems still?
Any help would be greatly appreciated.
Thanks,
Perry
Senior Member
Joined: Aug 2013
Posts: 1,243
Likes: 149
From: Gulfport MS
Your 97 used two sensors to read the temp. One in the intake and one in drivers side head. If I remember correctly the 2000 harness only uses the cht or head coolant temp.
As mentioned just install a aftermarket coolant temp gauge if you want a true reading.
As mentioned just install a aftermarket coolant temp gauge if you want a true reading.
I would just buy a ScanGauge bud. It would save you the trouble, and it would give you an accurate reading. It will also display 3 other gauges of your choice and show you how many miles until E!
Ford uses two different temperature sensors. One is called the engine coolant temperature (ECT) sensor and the other is the engine cylinder head temperature (CHT) sensor.
97-98 used ECT sensors. It is also imperative to notice your PCM uses this input to help control the Torque Converter Clutch. It used the temp readings as a strategy for the TCC.
THe ECT has a cone like shape at the bottom. The CHT is cyclinder shaped. Both are thermoresistors and use a fairly crude way to measure temperatures.
97-98 used ECT sensors. It is also imperative to notice your PCM uses this input to help control the Torque Converter Clutch. It used the temp readings as a strategy for the TCC.
THe ECT has a cone like shape at the bottom. The CHT is cyclinder shaped. Both are thermoresistors and use a fairly crude way to measure temperatures.
Its also important to note the CHT measures the temperature of the cyclinder head (without fluid crossing the sensor).
The ECT measures the tempature of a FLUID not a solid metal. Mixing these or a PCM that is made to measure one of the other is going to cause issues.
The ECT measures the tempature of a FLUID not a solid metal. Mixing these or a PCM that is made to measure one of the other is going to cause issues.