Another electric fan problem...
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From: St Simons Isl, GA
Another electric fan problem... Here's my setup. LS1 out of a 2000 Trans Am with the radiator and electric fans out of the same car went into my '75 Corvette. Wiring harness is a standalone unit from PSI.
Neither of my electric fans are coming on at any temp.
I am using two 40amp relays for the fans (one for each, obviously). Jon from PSI sent me a wiring diagram to use, and I followed it exactly. Here's how both fans are wired up...
I fused the power wire to each relay with a 20 amp fuse. I used a fuse that has a little red light in it to show that its getting power, and both are lit when the key is in the on position. I also verified power to the relay with a volt meter...about 10.5v. When the engine gets up to the temp where the fan is supposed to turn on, the signal wire from the PCM shows a signal as well...also about 10.5v. I'm using HPTuners to monitor engine temp, etc. I then tested the the terminal that supplies power to the fan itself....nothing. All three other terminals are showing 10.5v (roughly) when the engine reaches temp where the fan should turn on, but no signal whatsoever on the actual wire going to the fan.
I'm not certain I had the power and ground wire on the fan itself hooked up in the right place. I originally had power on the left, and ground on the right. I'm not sure if that's correct, and if it could be causing my problem. Other than that, I'm not sure what else to look for. Grounding issues? Relay issues?
Help.
Neither of my electric fans are coming on at any temp.
I am using two 40amp relays for the fans (one for each, obviously). Jon from PSI sent me a wiring diagram to use, and I followed it exactly. Here's how both fans are wired up...
I fused the power wire to each relay with a 20 amp fuse. I used a fuse that has a little red light in it to show that its getting power, and both are lit when the key is in the on position. I also verified power to the relay with a volt meter...about 10.5v. When the engine gets up to the temp where the fan is supposed to turn on, the signal wire from the PCM shows a signal as well...also about 10.5v. I'm using HPTuners to monitor engine temp, etc. I then tested the the terminal that supplies power to the fan itself....nothing. All three other terminals are showing 10.5v (roughly) when the engine reaches temp where the fan should turn on, but no signal whatsoever on the actual wire going to the fan.
I'm not certain I had the power and ground wire on the fan itself hooked up in the right place. I originally had power on the left, and ground on the right. I'm not sure if that's correct, and if it could be causing my problem. Other than that, I'm not sure what else to look for. Grounding issues? Relay issues?
Help.
What do you mean by "signal wire from PCM shows signal as well"? If you're using sensors that turn the fans on you would be bypassing the PCM. Have you tried unhooking the sensors and grounding that lead? If that turns them on then your sensor is bad or not making a good connection/ground. Using teflon tape on temp sensors will cause bad ground problems.
If you are using the PCM to control your fan(s),why is there a temp sensor in your diagram?Typically the PCM provides a ground for the relay coil when the temp is reached.If your connections at the fan are reversed,in most cases it will just turn the other direction.
Here's my setup. LS1 out of a 2000 Trans Am with the radiator and electric fans out of the same car went into my '75 Corvette. Wiring harness is a standalone unit from PSI.
Neither of my electric fans are coming on at any temp.
I am using two 40amp relays for the fans (one for each, obviously). Jon from PSI sent me a wiring diagram to use, and I followed it exactly. Here's how both fans are wired up...
I fused the power wire to each relay with a 20 amp fuse. I used a fuse that has a little red light in it to show that its getting power, and both are lit when the key is in the on position. I also verified power to the relay with a volt meter...about 10.5v. When the engine gets up to the temp where the fan is supposed to turn on, the signal wire from the PCM shows a signal as well...also about 10.5v. I'm using HPTuners to monitor engine temp, etc. I then tested the the terminal that supplies power to the fan itself....nothing. All three other terminals are showing 10.5v (roughly) when the engine reaches temp where the fan should turn on, but no signal whatsoever on the actual wire going to the fan.
I'm not certain I had the power and ground wire on the fan itself hooked up in the right place. I originally had power on the left, and ground on the right. I'm not sure if that's correct, and if it could be causing my problem. Other than that, I'm not sure what else to look for. Grounding issues? Relay issues?
Help.
Neither of my electric fans are coming on at any temp.
I am using two 40amp relays for the fans (one for each, obviously). Jon from PSI sent me a wiring diagram to use, and I followed it exactly. Here's how both fans are wired up...
I fused the power wire to each relay with a 20 amp fuse. I used a fuse that has a little red light in it to show that its getting power, and both are lit when the key is in the on position. I also verified power to the relay with a volt meter...about 10.5v. When the engine gets up to the temp where the fan is supposed to turn on, the signal wire from the PCM shows a signal as well...also about 10.5v. I'm using HPTuners to monitor engine temp, etc. I then tested the the terminal that supplies power to the fan itself....nothing. All three other terminals are showing 10.5v (roughly) when the engine reaches temp where the fan should turn on, but no signal whatsoever on the actual wire going to the fan.
I'm not certain I had the power and ground wire on the fan itself hooked up in the right place. I originally had power on the left, and ground on the right. I'm not sure if that's correct, and if it could be causing my problem. Other than that, I'm not sure what else to look for. Grounding issues? Relay issues?
Help.
What does this statement mean? " the signal wire from the PCM shows a signal as well...also about 10.5v"
Both a temp switch, in the diagram, and the ecu provide a ground to the relay for the fans to tun on.
Both a temp switch, in the diagram, and the ecu provide a ground to the relay for the fans to tun on.
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From: St Simons Isl, GA
Guys I apologize for not being clearer. I am not using a temp switch as shown in the diagram...the wire going to 86 on the relay is the wire from the PCM. I forgot that the diagram read that way before I posted it. Jon from PSI told me to substitute the PCM wire for the fan with the "temp switch" in the diagram.
So what I meant about the PCM wire showing a signal was this...when the engine reaches the temp where Fan1 is commanded to turn on by the PCM (as shown in the tune), terminal 86 on the relay is showing voltage (or a "signal" as I described it earlier) from the PCM. That voltage is about 10.5v.
So at this point, I am showing power to the relay on 30 and 85, and I am showing a "signal" from the PCM on 86 to turn the fan on. I am not showing voltage of any kind on the lead wire to the fan (87).
Hope that is clearer. Sorry for the confusion.
So what I meant about the PCM wire showing a signal was this...when the engine reaches the temp where Fan1 is commanded to turn on by the PCM (as shown in the tune), terminal 86 on the relay is showing voltage (or a "signal" as I described it earlier) from the PCM. That voltage is about 10.5v.
So at this point, I am showing power to the relay on 30 and 85, and I am showing a "signal" from the PCM on 86 to turn the fan on. I am not showing voltage of any kind on the lead wire to the fan (87).
Hope that is clearer. Sorry for the confusion.
Can you command them on with HPTuners? That would tell you if the wiring is right. Either that or unhook the PCM signal wire and ground it, that will turn the fans on if the wiring is right and the fans and relays are good.
On a side note, what temp are they set to come on? Are you sure you're reaching it?
On a side note, what temp are they set to come on? Are you sure you're reaching it?
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From: St Simons Isl, GA
I haven't tried to command them on with HPT. I don't guess I realized I could do that. I will give it a shot tonight. And I'll also try just grounding the PCM signal terminal.
Fan1 is set to come on at I think 207, and off at 199. I'm monitorin the water temp with HPT, so I'm sure its getting hot enough.
Fan1 is set to come on at I think 207, and off at 199. I'm monitorin the water temp with HPT, so I'm sure its getting hot enough.
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Hmm, maybe I am missing something, but from what i understand so far
1) You have two relays, one for each fan.. So each fan would only operate a single fan and one speed only (high speed) once given power from the relays.
2) you are using the PCM to signal the relays, Blue #42 for low and Red #33 for High (or in your case, just to activate the second fan/relay)
3) Your not using a temp/probe switch as the drawing shows.
4) you have both pins on the relay #30 and #85 to a fused battery hot.
5) the PCM should be sending a Grounding signal to the Relays #86 to activate the relay to power up the Fans.
So, as you are monitoring the engines temp and using HPT to do so, at 207 Deg, we would expect the ground circuit to be activated and your seeing a closed or completed circuit for or from the relay Pin #86.. Right?
As stated, pull the PCM wire on Pin #86 of the relay and ground it. it should activate the relay (pcm shoudl be out of the picture if doing so). .if you have power to both #30 and #85.. Power should be switched to #87 and the fans should come on, if not. the relay is bad !
Do you have a 4 or 5 pin relay #87 and #87a ?
BC
1) You have two relays, one for each fan.. So each fan would only operate a single fan and one speed only (high speed) once given power from the relays.
2) you are using the PCM to signal the relays, Blue #42 for low and Red #33 for High (or in your case, just to activate the second fan/relay)
3) Your not using a temp/probe switch as the drawing shows.
4) you have both pins on the relay #30 and #85 to a fused battery hot.
5) the PCM should be sending a Grounding signal to the Relays #86 to activate the relay to power up the Fans.
So, as you are monitoring the engines temp and using HPT to do so, at 207 Deg, we would expect the ground circuit to be activated and your seeing a closed or completed circuit for or from the relay Pin #86.. Right?
As stated, pull the PCM wire on Pin #86 of the relay and ground it. it should activate the relay (pcm shoudl be out of the picture if doing so). .if you have power to both #30 and #85.. Power should be switched to #87 and the fans should come on, if not. the relay is bad !
Do you have a 4 or 5 pin relay #87 and #87a ?
BC
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From: St Simons Isl, GA
Hmm, maybe I am missing something, but from what i understand so far
1) You have two relays, one for each fan.. So each fan would only operate a single fan and one speed only (high speed) once given power from the relays.
2) you are using the PCM to signal the relays, Blue #42 for low and Red #33 for High (or in your case, just to activate the second fan/relay)
3) Your not using a temp/probe switch as the drawing shows.
4) you have both pins on the relay #30 and #85 to a fused battery hot.
5) the PCM should be sending a Grounding signal to the Relays #86 to activate the relay to power up the Fans.
So, as you are monitoring the engines temp and using HPT to do so, at 207 Deg, we would expect the ground circuit to be activated and your seeing a closed or completed circuit for or from the relay Pin #86.. Right?
As stated, pull the PCM wire on Pin #86 of the relay and ground it. it should activate the relay (pcm shoudl be out of the picture if doing so). .if you have power to both #30 and #85.. Power should be switched to #87 and the fans should come on, if not. the relay is bad !
Do you have a 4 or 5 pin relay #87 and #87a ?
BC
1) You have two relays, one for each fan.. So each fan would only operate a single fan and one speed only (high speed) once given power from the relays.
2) you are using the PCM to signal the relays, Blue #42 for low and Red #33 for High (or in your case, just to activate the second fan/relay)
3) Your not using a temp/probe switch as the drawing shows.
4) you have both pins on the relay #30 and #85 to a fused battery hot.
5) the PCM should be sending a Grounding signal to the Relays #86 to activate the relay to power up the Fans.
So, as you are monitoring the engines temp and using HPT to do so, at 207 Deg, we would expect the ground circuit to be activated and your seeing a closed or completed circuit for or from the relay Pin #86.. Right?
As stated, pull the PCM wire on Pin #86 of the relay and ground it. it should activate the relay (pcm shoudl be out of the picture if doing so). .if you have power to both #30 and #85.. Power should be switched to #87 and the fans should come on, if not. the relay is bad !
Do you have a 4 or 5 pin relay #87 and #87a ?
BC
2. Correct, although keep in mind that I'm using a PSI harness which comes prewired with PCM wires for the fans.
3. Correct. The signal is coming from the PCM.
4. Correct. Those pins on the relays are receiving power.
5. Also correct.
At 207 degrees, my volt meter shows 10.5 on relay terminal 86. There is no output on the voltmeter on terminal 87 at this time.
Both relays are 40amp, 4 pin relays, bought new.
I will trying grounding terminal 86 to see what happens.
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From: St Simons Isl, GA
By the way (if anyone knows), what terminal on the fans themselves should the ground wire attach to and which should the power wire attach to? The terminals on each fan look like this:
___ ___
Thanks
___ ___
Thanks
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From: St Simons Isl, GA
OK, so I tried grounding terminal 86 and still got nothing. I even tried relocating the ground wires to the fans themselves, and no change. I can't figure anything else other than the relays at this point.
I couldn't make it to the auto parts store before they closed, so it'll have to wait until tomorrow. Is there anything specific I need to look for? 40amp relay is OK, right? I don't know if I bought a horn relay or anything like that...does it matter?
I couldn't make it to the auto parts store before they closed, so it'll have to wait until tomorrow. Is there anything specific I need to look for? 40amp relay is OK, right? I don't know if I bought a horn relay or anything like that...does it matter?
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From: St Simons Isl, GA
Zipster, I could give you a big hug. That's exactly what was wrong. The fuses light up when they are blown. I put a 30amp fuse in instead, and grounded the PCM terminal, and the fan fired right up.
Now I just need to know for sure what size fuse is proper for this setup.
Now I just need to know for sure what size fuse is proper for this setup.
That's funny, sometimes it's the simple things that trip you up. If you are running the oem fans from the camaro, run the fuse that is recommended for the fan set up. Or, run the fan with amp meter in the place of the fuse, take the reading in amps. If the fan pulls 5amps I would run a 15-20 amp fuse. Make sure the wiring from the relay to the fan is the same size as the wiring on the fan.
Well the fuse box and the wiring diagram for a F-Body specs a large 40amp fuse to drive Terminal #30 on both Relay #1 and #2.
A 10amp fuse to #85 on relay #1 and #2 along with #87 on Relay #3.
This is how I am running it on my Nova. For my Chevelle I run a Standalone controller, a SPAL PVM controller, I use a 30amp fuse on both SPAL fans.
I would say for your two Relay setup, start with a 30amp on Terminal #30 on both relays as the seem to be the power from the battery to the Fans, if that doesn hold, them use a 40amp.
Use a 10amp on Term #85 on the relay as they are for the switch in the relay.
BC
A 10amp fuse to #85 on relay #1 and #2 along with #87 on Relay #3.
This is how I am running it on my Nova. For my Chevelle I run a Standalone controller, a SPAL PVM controller, I use a 30amp fuse on both SPAL fans.
I would say for your two Relay setup, start with a 30amp on Terminal #30 on both relays as the seem to be the power from the battery to the Fans, if that doesn hold, them use a 40amp.
Use a 10amp on Term #85 on the relay as they are for the switch in the relay.
BC
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From: jacksonville,fl
Just thought i,d mention this on this thread, the f- body fans are nice, but not the highest quality motors. On my swap completed in early 03 , which I have put less than 10,000 miles on, I wired the fans stand alone to come on pretty quick. This caused the fans to wear prematurely with an end play issue, which causes off & on squealing. When I install my replacement motors, I'm trying out a different adjustable thermostat, which I will keep set to a higher temp.
Live & learn.
Live & learn.