Fan Control Temp Sensor '87 C4
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Fan Control Temp Sensor '87 C4
Installed Hypertech Temp sensor with chip. Sensor placed as instructed on data sheet (and shop manual) on passenger bank between cyl 3 & 4. When operating temp reached get over-temp reading on coolant readout on dash (oil temp fine). Radiator fan works. Info with sensor indicated that if sensor was installed incorrectly that fan would not come on.
Has anyone come across this issue?
Phil C
Has anyone come across this issue?
Phil C
- 1986 Original Owner -
Joined: Apr 1999
Posts: 3,193
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From: North Yorkshire, England
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Phil,
You really need to use the search function here as this has been done to death. Not sure what you use for a shop manual and I have no idea what the instruction sheet for this "Hypertech Temp Sensor" says, but the Sensor at the rear of the passenger side head (these are actually the even numbered cylinders - 2,4,6,8 - in this case the Sender/Sensor is located between 6 and 8) is for your instrument panel gauge only. What you removed was a perfectly good Sensor and installed a Switch. When temp is low the Switch you installed is open and your gauge reads LO. When the temp reaches closing temp of the Switch, the Switch closes and your gauge reads 299 and the red light comes on. Your gauge only reads LO or 299 with the over-temp light on (nothing in between) as the Switch only has two states, open or closed. You need to re-install your original Sensor.
The Switch you bought was designed to turn you Aux Fan on sooner or be wired into the Main Fan Relay. If you have an Aux Fan, you will have a Switch in the forward part of the driver side head, between cylinders 1 and 3. If you were to install your new Switch in place of this Switch, your Aux Fan would come on sooner. If you don't have an Aux Fan, there would be a plug here that would need to be removed to install the new Switch and then wired to the Main Fan Relay. Either way you say you also got a new Chip. This should be programmed to turn on the Main Fan sooner already. With the Main Fan on sooner, say 200°F instead of 226°F, the Aux Fan would be out of the picture unless the new Switch was closing at 195°F for example. In this case the Main Fan wouldn't come on as the Aux Fan would cool the engine before it reached the 200°F Fan turn on point burned into the new chip.
You need to let us know what you have (Aux Fan or No Aux Fan) and what you're trying to achieve.
You really need to use the search function here as this has been done to death. Not sure what you use for a shop manual and I have no idea what the instruction sheet for this "Hypertech Temp Sensor" says, but the Sensor at the rear of the passenger side head (these are actually the even numbered cylinders - 2,4,6,8 - in this case the Sender/Sensor is located between 6 and 8) is for your instrument panel gauge only. What you removed was a perfectly good Sensor and installed a Switch. When temp is low the Switch you installed is open and your gauge reads LO. When the temp reaches closing temp of the Switch, the Switch closes and your gauge reads 299 and the red light comes on. Your gauge only reads LO or 299 with the over-temp light on (nothing in between) as the Switch only has two states, open or closed. You need to re-install your original Sensor.
The Switch you bought was designed to turn you Aux Fan on sooner or be wired into the Main Fan Relay. If you have an Aux Fan, you will have a Switch in the forward part of the driver side head, between cylinders 1 and 3. If you were to install your new Switch in place of this Switch, your Aux Fan would come on sooner. If you don't have an Aux Fan, there would be a plug here that would need to be removed to install the new Switch and then wired to the Main Fan Relay. Either way you say you also got a new Chip. This should be programmed to turn on the Main Fan sooner already. With the Main Fan on sooner, say 200°F instead of 226°F, the Aux Fan would be out of the picture unless the new Switch was closing at 195°F for example. In this case the Main Fan wouldn't come on as the Aux Fan would cool the engine before it reached the 200°F Fan turn on point burned into the new chip.
You need to let us know what you have (Aux Fan or No Aux Fan) and what you're trying to achieve.
Ray speaks the truth 
