Low Temperature Fan Switch ?
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From: Dallas TX
Low Temperature Fan Switch ?
LOW TEMPERATURE FAN SWITCH
Got 1995 with an LT1 here. Have this switch I am working on.
There are two cooling temp sensors I believe. One between the 6 & 8 cylinder, and the other on the water pump. Now the instructions from corvette central (and my instincts) dictate that the one on the manifold is the one I need to swap. However, the new one has two wires...exactly as the one off the pump
Am I really just supposed to swap the one at the water pump here? Kinda losing it today, my apologies
Got 1995 with an LT1 here. Have this switch I am working on.
There are two cooling temp sensors I believe. One between the 6 & 8 cylinder, and the other on the water pump. Now the instructions from corvette central (and my instincts) dictate that the one on the manifold is the one I need to swap. However, the new one has two wires...exactly as the one off the pump
Am I really just supposed to swap the one at the water pump here? Kinda losing it today, my apologies
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From: Dallas TX
Originally Posted by STL94LT1
Your insticts are right. The coolant temp sensor in the water pump sends a signal to the PCM, and shouldn't be removed.
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From: The Top of Utah
The instructions are correct. Since you don't have a sensor/sender in the intake manifold, don't install the switch. The sensor (not a switch) in your water pump reports to the ECM, PCM, or what ever a '95 has and the info is used for ALL the engine, temperature related functions, like a rich, choke like, mixture when cold, and a cold idle. Both your fans are controlled by the ec... computer. There is no way a switch or recalibration of the sensor will alter the fan on/off temps and allow the engine to run. You will have to have your computer re-flashed to the temps you want.
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From: Dallas TX
Originally Posted by CFI-EFI
The instructions are correct. Since you don't have a sensor/sender in the intake manifold, don't install the switch. The sensor (not a switch) in your water pump reports to the ECM, PCM, or what ever a '95 has and the info is used for ALL the engine, temperature related functions, like a rich, choke like, mixture when cold, and a cold idle. Both your fans are controlled by the ec... computer. There is no way a switch or recalibration of the sensor will alter the fan on/off temps and allow the engine to run. You will have to have your computer re-flashed to the temps you want.
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Originally Posted by corvette central
-85-89 with B4P, 90-95 All.
-Lowers engine coolant temperature
-Maximizes engine performance
The stock C4 Corvette cooling system runs inherently hot. GMP has the solution. We offer electric cooling fan switches in four different temperature ranges. The switches will turn on the main fan, auxiliary fan or both at a lower temperature. Lower coolant temperatures will maximize engine performance and reduce engine wear. Each kit comes complete with switch, harness, hardware and instructions for easy installation. 244455 and 244074 switches are recommended for stock applications.
-Lowers engine coolant temperature
-Maximizes engine performance
The stock C4 Corvette cooling system runs inherently hot. GMP has the solution. We offer electric cooling fan switches in four different temperature ranges. The switches will turn on the main fan, auxiliary fan or both at a lower temperature. Lower coolant temperatures will maximize engine performance and reduce engine wear. Each kit comes complete with switch, harness, hardware and instructions for easy installation. 244455 and 244074 switches are recommended for stock applications.
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From: The Top of Utah
I'd have to see what that harness consists of, or see a schematic for it. Starting in 1990 both fans were computer controlled. It would be possible to rig up a switch, like yours, and wiring to take the function away from the computer, but you would have to jump through some serious hoops to have them (it) shut off at 30 mph, like the computer does.
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Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
Not really that complicated. - The switch screws into a boss in the left head which is now plugged. You take the ground side of the Relay(s) which now run to the PCM and splice them into the switch. The Relay(s) will then be grounded at whatever temperature controls (closes) the switch. You splice, instead of eliminating the PCM control, because the PCM also grounds the Relays based on the signal from the a/c pressure sensor and it does that at a condensor temp of about 100 to 130 degrees - far lower than any switch. Remove that control and you won't have much of an a/c system. With this setup, you will give up PCM control of the fans at cruise. Most are programmed to turn off (remove ground) the fans at 45 mph or so. Yours will continue to turn until the coolant temp drops below whatever threshold is designed into the switch.
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From: The Top of Utah
Originally Posted by SunCr
With this setup, you will give up PCM control of the fans at cruise. Most are programmed to turn off (remove ground) the fans at 45 mph or so. Yours will continue to turn until the coolant temp drops below whatever threshold is designed into the switch.
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From: Dallas TX
Originally Posted by BADDUCK
That's normal.
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From: The Top of Utah
That isn't because the temps are too high. That is because the water pump is in the way out. I would stop driving the car until I could replace the water pump, or you will be buying a new opti spark (for hundreds) too.
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Pro
Joined: Aug 2004
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Originally Posted by 956Vette
Yes sir. However, I fear that the range of temps is causing havoc. When it gets too hot the underside of teh water pump has a hole (pardon my terminology). Basically the water pump will spit out coolant, which gets flung on the belt...and you can only imagine what my engine compartment/hood looks like after teh blow up. I also lose power steering and others because of the **** on teh belt for a period of time...not good. The pump is probably 4-5yrs old now, but in good working order as far as I can tell
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From: The Top of Utah
Originally Posted by 956Vette
Wow, ouch. Thanks so much for the heads up guys! I know for a fact that I had both the opti-spark unit and pump replaced...hasnt even seen 20k miles 
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