Why would a low temp switch require power, when it sends ground back to fan relay ??
Engine Temp Sensor
Thread Starter
Safety Car
Joined: Jul 2003
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Engine Temp Sensor
In cleaning my engine bay and wiring, I've found a quick fix someone has done which needs to be done right. It looks like the one wire connector has gotten smashed at some time and was replaced by a two wire connector. They have wired one into the old existing one wire connector and the other wire into a positive power wire to the fuel pump. See pics below.
Questions- Can the one wire connector be found? Can I not splice this back into the original wire and remove the two wire splice? What do you think?
Drivers side of engine between 1 and 3 cylinders.
Old smashed connector with black wire spliced in.
Red wire spliced into fuel pump power.
Questions- Can the one wire connector be found? Can I not splice this back into the original wire and remove the two wire splice? What do you think?
Drivers side of engine between 1 and 3 cylinders.
Old smashed connector with black wire spliced in.
Red wire spliced into fuel pump power.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
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From: Santa Maria CA
That is an aftermarket low temperature fan switch that a previous owner installed to turn the fans on sooner. It taps into the fan relay harness. Those quick splice connectors and that two wire plug came in the kit.
http://www.mamotorworks.com/corvette-3-138-944.html
Single or dual fan on your car? If dual, he replaced the stock "auxillary" fan switch right there between #1 and #3 with the new switch and two wire harness. If single fan, he removed a factory pipe plug and added the switch.
Your guage temp sender is on the opposite side between 6 and 8. The temp sender for the computer is threaded into the intake manifold.
http://www.mamotorworks.com/corvette-3-138-944.html
Single or dual fan on your car? If dual, he replaced the stock "auxillary" fan switch right there between #1 and #3 with the new switch and two wire harness. If single fan, he removed a factory pipe plug and added the switch.
Your guage temp sender is on the opposite side between 6 and 8. The temp sender for the computer is threaded into the intake manifold.
Last edited by 86PACER; Dec 1, 2009 at 02:20 AM.
Le Mans Master
Joined: Aug 2000
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From: Australia
Mike @ EFI Connection has what you want
http://www.eficonnection.com/eficonn..._pigtails.aspx
Same connector as knock sensor
http://www.eficonnection.com/eficonn..._pigtails.aspx
Same connector as knock sensor
Thread Starter
Safety Car
Joined: Jul 2003
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My car does have the dual fans. I've asked a guy at napa but he didn't think he had it. I can ask for a knock sensor connector though, maybe he could find that.
I've had a new chip programed when the car was tuned after the new engine. The tuner set the fans to come on earlier. Do I still need this connector?
I've had a new chip programed when the car was tuned after the new engine. The tuner set the fans to come on earlier. Do I still need this connector?
Melting Slicks
Joined: Feb 2008
Posts: 3,286
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From: Palm Beach
Depends on how it was wired. The ECM does not normally control the fan in front of the radiator.
My car does have the dual fans. I've asked a guy at napa but he didn't think he had it. I can ask for a knock sensor connector though, maybe he could find that.
I've had a new chip programed when the car was tuned after the new engine. The tuner set the fans to come on earlier. Do I still need this connector?
I've had a new chip programed when the car was tuned after the new engine. The tuner set the fans to come on earlier. Do I still need this connector?
Thread Starter
Safety Car
Joined: Jul 2003
Posts: 4,928
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Is the harness what really makes the difference or the sensor?
If my temp sensor is original, then would a two wire harness turn the fan on faster? Wouldn't I need a different sensor? And if the sensor is the aftermarket, wouldn't it still turn on the fan with the original harness at the lowered temp? I'm just not seeing the reason for installing the two wire system. But I'm no wiring expert for sure! Can someone explain?
If my temp sensor is original, then would a two wire harness turn the fan on faster? Wouldn't I need a different sensor? And if the sensor is the aftermarket, wouldn't it still turn on the fan with the original harness at the lowered temp? I'm just not seeing the reason for installing the two wire system. But I'm no wiring expert for sure! Can someone explain?
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Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
(both wires go to ground when closed )
The red to the main fan relay ground and the black cut into the Aux fan ground wire
This is a option in the install instructions for two wire switches
http://www.ecklers.com/assets/pdf/40416.pdf?
Last edited by rodj; Dec 2, 2009 at 01:42 AM.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
both relays at the same time
You have the green wire from front so you must have the Aux fan.It is only controlled by whatever switch is installed in the shown location ; not by the computer which only controls main fan
Team Owner
Joined: Jan 2003
Posts: 20,320
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From: Summerland B.C. Canada
In this instance it looks as if the one switch has been used to turn on both fans
(both wires go to ground when closed )
The red to the main fan relay ground and the black cut into the Aux fan ground wire
This is a option in the install instructions for two wire switches
http://www.ecklers.com/assets/pdf/40416.pdf?
(both wires go to ground when closed )
The red to the main fan relay ground and the black cut into the Aux fan ground wire
This is a option in the install instructions for two wire switches
http://www.ecklers.com/assets/pdf/40416.pdf?
The OP says it's wired into his fuel pump relay, when looking at his pic, it's exactly where my fuel pump relay is.
I just can't see why those wires aren't fried.
Le Mans Master
Joined: Sep 2006
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From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
I think maybe they just used the original grounding wire as a positive source because the wire was already installed, and put a new relay in somewhere.
That's what it looks like.
In effect, the fuel pump relay provides power to the temp sensor location, and the new relay uses that power to run the fans, if the "kit" installs a relay and grounds the wire near the fan(s)
That's what it looks like.
In effect, the fuel pump relay provides power to the temp sensor location, and the new relay uses that power to run the fans, if the "kit" installs a relay and grounds the wire near the fan(s)
Le Mans Master
Joined: Jun 2006
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From: One day you're a Comet...the next day you're dust... Arkansas
IMO it's probably not a great idea to turn both fans on simultaneously at a low temp. I turn my aux fan on in my 1989 early at @ 200* and left the main fan control to the ECM at the stock temp. That has worked great for the last two years.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
