anyway to test a relay ?
Thread Starter
Drifting
Joined: Nov 2003
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From: South al
anyway to test a relay ?
Bill curlee where are u when i need ya
what i am wondering is ,is there a way i can test a relay before i just start swapping them out,i have an electrical gremlin & i keep blowing cooling fans maxifuses @ 4.00 a peice there starting to get high ,didnt wanna buy new relays without testing them , also i was thinking about running toggle switches & run the wire direct instead of having to troubleshoot wiring ,anyone done this , i appreciate any feed back , thank you
what i am wondering is ,is there a way i can test a relay before i just start swapping them out,i have an electrical gremlin & i keep blowing cooling fans maxifuses @ 4.00 a peice there starting to get high ,didnt wanna buy new relays without testing them , also i was thinking about running toggle switches & run the wire direct instead of having to troubleshoot wiring ,anyone done this , i appreciate any feed back , thank you
Pro
Joined: Dec 2003
Posts: 654
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From: chandler az
A relay is just a switch triggered with a voltage. In the case of a car, it usualy 12v that turns the switch on. On magnetic types on a lot of automotive applications you can hear it "click".
You can use a meter to test for a short when the voltage is applied.
Do you know which pins to apply the 12v and which to test for a short?
Using a toggle switch is an easy way to bypass the relay for testing. Just be sure you use a heavy enough guage wire and switch that is rated for the application. I don't know what your fans are rated at, but 40-50 amps is not unusual for stuff like that because of the startup current needed to bring the fans up to speed, which means you are needing a fairly heavy duty switch.
You can use a meter to test for a short when the voltage is applied.
Do you know which pins to apply the 12v and which to test for a short?
Using a toggle switch is an easy way to bypass the relay for testing. Just be sure you use a heavy enough guage wire and switch that is rated for the application. I don't know what your fans are rated at, but 40-50 amps is not unusual for stuff like that because of the startup current needed to bring the fans up to speed, which means you are needing a fairly heavy duty switch.
Melting Slicks
Joined: Oct 2007
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From: Kinston North Carolina
Racer
Joined: May 2006
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Blowing the fuses? Sounds like over current, the relay couldn't cause that, it's just turning it on/off. Sounds like a bad fan motor, it's got something shorted out in the motor. You need to hookup a current meter inline with the motor and see how many amps it pulls. Also need to find out what the normal motor pulls. Tell me which fan and I can measure it on my coupe. I have a clamp on type amp meter that would work for this.
Good Luck...
DocOhm
Good Luck...
DocOhm
Thread Starter
Drifting
Joined: Nov 2003
Posts: 1,539
Likes: 3
From: South al
Blowing the fuses? Sounds like over current, the relay couldn't cause that, it's just turning it on/off. Sounds like a bad fan motor, it's got something shorted out in the motor. You need to hookup a current meter inline with the motor and see how many amps it pulls. Also need to find out what the normal motor pulls. Tell me which fan and I can measure it on. Something out of this, thanks for the help guysmy coupe. I have a clamp on type amp meter that would work for this.
Good Luck...
DocOhm
Good Luck...
DocOhm
Last edited by fsuforever; Jun 22, 2009 at 07:09 PM.
Racer
Joined: May 2006
Posts: 352
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. U hit the nail on the head,the low speed settings would work fine for minumim cooling. But for high speed /max cooling when both fans are in operation only 1 fan ,the lh fan would work & the 2nd would blow a fuse ,resistance on the high speed fan was causing the rh fan to not function @ high coolant temps & would blow maxifuse 46 cooling fan relay 2,only @ high temps is when it would blow t,the RH FAn is reading high ohms /resistance vs the left sidefan,maybe someone else can get something out of this, I opted to put these in my vette ,I just cut the metric connectors & hard wired them into the new spal fans ,but retained the old shroudfor the tabs on the ends [url]www.universalpartsinc.com/detail.asp?part=30102052+
Something doesn't sound right HIGH resistance will not blow fuses. LOW resistance will. If the fuse blows when the RH fan comes on but works OK with just one fan it sounds like the RH fan has a short (low resistance) and is pulling too much current blowing the fuse.
I can't get my DVD service manual to work today so I can't lookup the circuit. I'll see if I can fix that and let you know what to do next.
I'm think you should be able to put a certain sized fuse on a wire and direct connect from the pos on the battery to the power side of the fan. Problem is, sometimes they switch the neg side of devices not the pos side.
Did you actually put an ohm meter across both fan motors? What were the readings?
Docohm
Racer
Joined: Feb 2004
Posts: 359
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From: St. Paul MN
Diagram
Larger size
The fan shroud electrical fan motors drive the engine cooling fans. The fan shroud is located at the base of the radiator. The fan motors both have five blades that are each 312 mm (12.3 in) in diameter. The blades operate at two speeds, high and low.
The engine cooling fan relays provide the high current required for the motors, based on a ground signal received from the power control module (PCM).
The cooling fan relays are used to control the high current flow to power the cooling fan motors. Both fans operate together. When minimum cooling is required, the PCM energizes CoolFan1(#45) and both fans operate at low speed, since the fans are connected in series through CoolFan2 (#43) and CoolFan3 (#44). When maximum cooling is required, the PCM energizes all three cooling fan relays. The left fan is still powered through CoolFan1, but is now grounded through CoolFan3. The right fan is now powered directly through CoolFan2 and both fans operate at high speed.
The engine cooling fan relays provide the high current required for the motors, based on a ground signal received from the power control module (PCM).
The cooling fan relays are used to control the high current flow to power the cooling fan motors. Both fans operate together. When minimum cooling is required, the PCM energizes CoolFan1(#45) and both fans operate at low speed, since the fans are connected in series through CoolFan2 (#43) and CoolFan3 (#44). When maximum cooling is required, the PCM energizes all three cooling fan relays. The left fan is still powered through CoolFan1, but is now grounded through CoolFan3. The right fan is now powered directly through CoolFan2 and both fans operate at high speed.
Todd
Last edited by toddk; Jun 22, 2009 at 11:24 PM.
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Racer
Joined: May 2006
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That's a great diagram and writeup! Thanks for posting.
From that and fsuforever's posting it looks to me like minirelay 44 may be bad.
Try this, pull that relay. Start 'er up and let her get hot. It should eventually try to go into high on both fans, without R44 it CAN'T get a ground to the LH fan so it shouldn't come one. It CAN get power and ground to the RH fan so it should come on full speed.
If that works you've proven that R44 is bad and needs to be replaced OR the PCM is not actually turn on all THREE relays when it's supposed to.
If R43 turns on an R44 doesn't it trys to backfeed power to the LH fan. Not good.
Now that we have a schematic we can fix it! With a little troubleshooting....
DocOhm
From that and fsuforever's posting it looks to me like minirelay 44 may be bad.
Try this, pull that relay. Start 'er up and let her get hot. It should eventually try to go into high on both fans, without R44 it CAN'T get a ground to the LH fan so it shouldn't come one. It CAN get power and ground to the RH fan so it should come on full speed.
If that works you've proven that R44 is bad and needs to be replaced OR the PCM is not actually turn on all THREE relays when it's supposed to.
If R43 turns on an R44 doesn't it trys to backfeed power to the LH fan. Not good.
Now that we have a schematic we can fix it! With a little troubleshooting....
DocOhm
Drifting
Joined: Jan 2001
Posts: 1,347
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From: Slidell La
I am really thinking you have a bad fan motor to blow the fuses. The relays energize and that is when the load exceeds the fuse and it blows.
I suspect shorted fan wiring which will give LOW resistance.
I suspect shorted fan wiring which will give LOW resistance.
Racer
Joined: May 2006
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DocOhm
Drifting
Joined: Jan 2001
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From: Slidell La
But if you look at the schematic and write up, BOTH fans operate in series at low speed and that is working fine. If one fan were bad (shorted) then only one fan would run on low speed and it would run FAST (high speed). I think it's that 3rd relay not working. We'll have to wait and hear back from fsu for more test results.
DocOhm
DocOhm
Team Owner
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Sometimes electrical motors blow fuses because they are drawing too much current because the bearing(s) or bushing(s) is/are bad and creating a lot of friction (drag).
Drifting
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From: Slidell La
Tech Contributor
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From: Forney Texas
It could also be that your Spal fans draw more current than factory. When starting an electrical motor, current leads voltage, meaning there is a huge in rush of current at the startup of the motor. When you have one fan running and then kick on another, the startup load could be just enough to blow the fuse. You may try reversing the responsibility of the fans so the other one comes on first and see if it blows the fuse or not. If it doesn't, what I'm saying could be a reality.
Thread Starter
Drifting
Joined: Nov 2003
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From: South al
Ok ,what I did was I got the car up to temps 194 ,with the hood up the 2nd fan/rh fan tried to come on & blew maxifuse 46,so I pulled the fans out of the car & hard wired the lh fan directly to the battery & it performed extremley well, I hooked the right fan/RH fan up directly to the battery & my girl could blow harder with her mouth faster than the rh fan was blowing , I am in the process today of hooking up the new spal fans ,I took the old fan shroud & the new spal fans & a metabo blade & made this work with it rivited into the 00 fan shroud,there are some nicer shrouds out there that are made of metal ,I am the type that will make applecider out of 1 apple,I will post pics of the new shroud soon, so the old rh fan motor was causing the maxifuse 46 to blow ,I appreciate everyones help & input on this matter,fsuforever 
Last edited by fsuforever; Jun 24, 2009 at 12:36 PM.
Tech Contributor
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From: Dyer, IN
Ok ,what I did was I got the car up to temps 194 ,with the hood up the 2nd fan/rh fan tried to come on & blew maxifuse 46,so I pulled the fans out of the car & hard wired the lh fan directly to the battery & it performed extremley well, I hooked the right fan/RH fan up directly to the battery & my girl could blow harder with her mouth faster than the rh fan was blowing , I am in the process today of hooking up the new spal fans ,I took the old fan shroud & the new spal fans & a metabo blade & made this work with it rivited into the 00 fan shroud,there are some nicer shrouds out there that are made of metal ,I am the type that will make applecider out of 1 apple,I will post pics of the new shroud soon, so the old rh fan motor was causing the maxifuse 46 to blow ,I appreciate everyones help & input on this matter,fsuforever
Thread Starter
Drifting
Joined: Nov 2003
Posts: 1,539
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From: South al
nope ,no fuse , i hooked it directly to the battery, i guess i am the 1st one to do this
,so let the flaming begin
http://www.universalpartsinc.com/default.asp
,so let the flaming begin http://www.universalpartsinc.com/default.asp
Last edited by fsuforever; Jun 24, 2009 at 12:43 PM.
Tech Contributor
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From: Dyer, IN
nope ,no fuse , i hooked it directly to the battery, i guess i am the 1st one to do this ,so let the flaming begin http://www.universalpartsinc.com/default.asp
,so let the flaming begin http://www.universalpartsinc.com/default.asp
Drifting
Joined: Jan 2001
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From: Slidell La
I would assume you did hook directly to the battery and not through the car wire harness. I suspect the fan motor has shorted internal wiring with low resistance and pulling too much current. This short is why it turns slow.
I have heard there are replacement fans at parts stores that are exact replacements. Can you get me a part number off the OEM fan. I would like to confirm my data to see if there are replacement motors. A photo of the name tag would be great. Thank you in advance. If you can't get it I will just keep searching. vettdvr.
I have heard there are replacement fans at parts stores that are exact replacements. Can you get me a part number off the OEM fan. I would like to confirm my data to see if there are replacement motors. A photo of the name tag would be great. Thank you in advance. If you can't get it I will just keep searching. vettdvr.