Fan switch and SES light
Thread Starter
Staging Lane
Joined: Dec 2004
Posts: 82
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From: Grand Forks, ND
Fan switch and SES light Does anyone know what causes the SES light I've been reading about with the manual fan switch? It seems the light comes on when the computer tries to turn the fans on, when you already have them on. I'm going by the setup at http://users.oco.net/xero/fanmod/ and it seems pretty bullet proof, but still, I've been hearing about this SES light..
Can anyone provide some insight on this problem before I attempt this mod? I would have no problems installing it, I'm just worried about the SES.
Thanks!
Can anyone provide some insight on this problem before I attempt this mod? I would have no problems installing it, I'm just worried about the SES.
Thanks!
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Joined: May 2005
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From: Charlotte, NC
Thats a common problem with people who follow the directions provided on that switch. I have been making and selling manual fan switchs for a while now. I use a different design. This prevents the SES from coming on. It's only a problem on OBDII vehicles. Without giving away my design I can't say much but basicly the computer is seeing a ground feedback when you activate the switch and thinks that there is a cuircut problem.
I never cared much for that write up. I use a totaly different system that doesn't set an SES, that uses 12 volt LED's, that doesn't need a Switched hot feed for the LED's etc etc etc
The SES isn't going to "harm" anything other then it being annoying.
I never cared much for that write up. I use a totaly different system that doesn't set an SES, that uses 12 volt LED's, that doesn't need a Switched hot feed for the LED's etc etc etc
The SES isn't going to "harm" anything other then it being annoying.
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Thread Starter
Staging Lane
Joined: Dec 2004
Posts: 82
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From: Grand Forks, ND
Okay, good info thus far.
How is the SLP switch set up? What do you have to do to install it? By knowing this, I can better understand how they get around the SES problem. I'm not trying to step on anyones toes, I'm just trying to better understand the F-body's electrical system and how to make it do what I want.
Can anyone else offer some technical insight? What do those two wires that I tap into do in the install linked in my first post? The H&J wires? How does the computer control the fans? What happens when the computer sends out the 'on' signal for both the low and high speed fans?
How is the SLP switch set up? What do you have to do to install it? By knowing this, I can better understand how they get around the SES problem. I'm not trying to step on anyones toes, I'm just trying to better understand the F-body's electrical system and how to make it do what I want.
Can anyone else offer some technical insight? What do those two wires that I tap into do in the install linked in my first post? The H&J wires? How does the computer control the fans? What happens when the computer sends out the 'on' signal for both the low and high speed fans?
Last edited by Marksman; May 9, 2005 at 11:19 PM.
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SLp prevents the computer from seeing a ground to the fan relays as said above.
The fan relays need a ground to turn on. J is the low speed fan output of the comptuer, where H is the high speed fan output.
While I am not sure how HBH's kits work, as they appear to splice into the fan harness which cannot use the same method as SLP's. my design is similar to slp's, but to build one like this, requires cutting and splicing into the H and J wires if your not using the weather pack connectors for a professional plug and play method.
Without cutting factory harnesses, the other method I know of is to add a 47 ohm 2 watt resitor inline to the J wire, somewhere between the switch and the splice and use 2 47 ohm resistors in parallel between the switch and wher you splice into the H wire, you will also prevent the ses lights, however this method the fan switch does not provide a full ground, but in long term testing (2-3 years) the people who I have seen with this method does not have a problem.
Ryan
The fan relays need a ground to turn on. J is the low speed fan output of the comptuer, where H is the high speed fan output.
While I am not sure how HBH's kits work, as they appear to splice into the fan harness which cannot use the same method as SLP's. my design is similar to slp's, but to build one like this, requires cutting and splicing into the H and J wires if your not using the weather pack connectors for a professional plug and play method.
Without cutting factory harnesses, the other method I know of is to add a 47 ohm 2 watt resitor inline to the J wire, somewhere between the switch and the splice and use 2 47 ohm resistors in parallel between the switch and wher you splice into the H wire, you will also prevent the ses lights, however this method the fan switch does not provide a full ground, but in long term testing (2-3 years) the people who I have seen with this method does not have a problem.
Ryan
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From: Charlotte, NC
slow is pretty much right.
I chose to make mine without the metri-pack connectors because of the cost. Thats one reason that SLP and other switchs like them are so expensive. I can get away with out plug and play since "most" people don't have a hard time following the directions and doing some simple wireing to install them. From a personal standpoint I just don't like the SLP switch because it's bulky, has the extra metri-pack connector taking up room, and offers no features like LED's etc etc. Couple that with it's price and thats the reason that I made my own. After coming up with a good design after about 2 years of playing I started selling them. I haven't had issues with mine or any that I have sold yet. Mine has been through some small changes but I have been running it for a little over 3 years.
I guess in the end there are a lot of choices out there. It really all depends on what you would like to do. OBDI is really easy to do. The only issue is when you shut the car off and the hot feed at the relay coil goes away the ground can feedback and leave LED's on, but this is rather easy to get around. OBDII the only obsticle is SES lights which is also easy to get around.
I chose to make mine without the metri-pack connectors because of the cost. Thats one reason that SLP and other switchs like them are so expensive. I can get away with out plug and play since "most" people don't have a hard time following the directions and doing some simple wireing to install them. From a personal standpoint I just don't like the SLP switch because it's bulky, has the extra metri-pack connector taking up room, and offers no features like LED's etc etc. Couple that with it's price and thats the reason that I made my own. After coming up with a good design after about 2 years of playing I started selling them. I haven't had issues with mine or any that I have sold yet. Mine has been through some small changes but I have been running it for a little over 3 years.
I guess in the end there are a lot of choices out there. It really all depends on what you would like to do. OBDI is really easy to do. The only issue is when you shut the car off and the hot feed at the relay coil goes away the ground can feedback and leave LED's on, but this is rather easy to get around. OBDII the only obsticle is SES lights which is also easy to get around.
12 Second Club
Joined: May 2004
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From: hazelwood,Mo.
Originally Posted by HBHRacing
slow is pretty much right.
I chose to make mine without the metri-pack connectors because of the cost. Thats one reason that SLP and other switchs like them are so expensive. I can get away with out plug and play since "most" people don't have a hard time following the directions and doing some simple wireing to install them. From a personal standpoint I just don't like the SLP switch because it's bulky, has the extra metri-pack connector taking up room, and offers no features like LED's etc etc. Couple that with it's price and thats the reason that I made my own. After coming up with a good design after about 2 years of playing I started selling them. I haven't had issues with mine or any that I have sold yet. Mine has been through some small changes but I have been running it for a little over 3 years.
I guess in the end there are a lot of choices out there. It really all depends on what you would like to do. OBDI is really easy to do. The only issue is when you shut the car off and the hot feed at the relay coil goes away the ground can feedback and leave LED's on, but this is rather easy to get around. OBDII the only obsticle is SES lights which is also easy to get around.
I chose to make mine without the metri-pack connectors because of the cost. Thats one reason that SLP and other switchs like them are so expensive. I can get away with out plug and play since "most" people don't have a hard time following the directions and doing some simple wireing to install them. From a personal standpoint I just don't like the SLP switch because it's bulky, has the extra metri-pack connector taking up room, and offers no features like LED's etc etc. Couple that with it's price and thats the reason that I made my own. After coming up with a good design after about 2 years of playing I started selling them. I haven't had issues with mine or any that I have sold yet. Mine has been through some small changes but I have been running it for a little over 3 years.
I guess in the end there are a lot of choices out there. It really all depends on what you would like to do. OBDI is really easy to do. The only issue is when you shut the car off and the hot feed at the relay coil goes away the ground can feedback and leave LED's on, but this is rather easy to get around. OBDII the only obsticle is SES lights which is also easy to get around.
setting offf the ses light so I removed the switch.
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From: Charlotte, NC
Originally Posted by john shea
I modded a fan switch in my car and it kept
setting offf the ses light so I removed the switch.
setting offf the ses light so I removed the switch.
without seeing exactly what you did I can't tell you why. RIght now I have....5 people running mine on an OBDII system and have no problems. The "ultimate write up" is very popular for people to use which is too bad because it will always set an SES. There are about 3 other companys out there that make fan switchs for us. The only that I have worked with is the SLP which I didn't like. The other is by Jet which really just takes a ground switch and has you mount it into the pass side head. once it reaches a certain temp it will ground the wires for the fans and turn them on. this requires a lot of work and will NOT work on OBDII. It's also very expensive for what you get.
Thread Starter
Staging Lane
Joined: Dec 2004
Posts: 82
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From: Grand Forks, ND
Thanks for all the info so far, it's helped me quite a bit!
So, if the H & J wires send the signal to turn the fans on, really, all you SHOULD need to do is supply power to them., which is what that write up does. However this is not the case, because I'm guessing the computer sees that power has been added to that line without it's knowledge and that's what sets the SES. I suppose you could put resistors between where you spliced in and the computer, as mentioned above, so the computer doesnt see the voltage, but then would that affect the normal opperation?
You also COULD send power directly to the fans, but that would require a mega huge switch and wiring which nobody wants to work with. I may have to try the resistor thing, if indeed the voltage that you add to the H&J wires is what trips the SES. I'm gonna do some reading on ground loops as well to try and better understand those.
I take it the H & J wires simply send the 'on' voltage to a relay?
So, if the H & J wires send the signal to turn the fans on, really, all you SHOULD need to do is supply power to them., which is what that write up does. However this is not the case, because I'm guessing the computer sees that power has been added to that line without it's knowledge and that's what sets the SES. I suppose you could put resistors between where you spliced in and the computer, as mentioned above, so the computer doesnt see the voltage, but then would that affect the normal opperation?
You also COULD send power directly to the fans, but that would require a mega huge switch and wiring which nobody wants to work with. I may have to try the resistor thing, if indeed the voltage that you add to the H&J wires is what trips the SES. I'm gonna do some reading on ground loops as well to try and better understand those.
I take it the H & J wires simply send the 'on' voltage to a relay?
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From: Charlotte, NC
Originally Posted by Marksman
Thanks for all the info so far, it's helped me quite a bit!
So, if the H & J wires send the signal to turn the fans on, really, all you SHOULD need to do is supply power to them., which is what that write up does. However this is not the case, because I'm guessing the computer sees that power has been added to that line without it's knowledge and that's what sets the SES. I suppose you could put resistors between where you spliced in and the computer, as mentioned above, so the computer doesnt see the voltage, but then would that affect the normal opperation?
You also COULD send power directly to the fans, but that would require a mega huge switch and wiring which nobody wants to work with. I may have to try the resistor thing, if indeed the voltage that you add to the H&J wires is what trips the SES. I'm gonna do some reading on ground loops as well to try and better understand those.
I take it the H & J wires simply send the 'on' voltage to a relay?
So, if the H & J wires send the signal to turn the fans on, really, all you SHOULD need to do is supply power to them., which is what that write up does. However this is not the case, because I'm guessing the computer sees that power has been added to that line without it's knowledge and that's what sets the SES. I suppose you could put resistors between where you spliced in and the computer, as mentioned above, so the computer doesnt see the voltage, but then would that affect the normal opperation?
You also COULD send power directly to the fans, but that would require a mega huge switch and wiring which nobody wants to work with. I may have to try the resistor thing, if indeed the voltage that you add to the H&J wires is what trips the SES. I'm gonna do some reading on ground loops as well to try and better understand those.
I take it the H & J wires simply send the 'on' voltage to a relay?
Thread Starter
Staging Lane
Joined: Dec 2004
Posts: 82
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From: Grand Forks, ND
I think I'm going to go with the resistor idea the slow and HBH brought up. I'll give that a shot next week when I'm home and able to work on it in my garage. After some careful consideration and research I think it should prevent the SES light from popping up.
