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Jonesin'

Relay info

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I will be running a Switch Pro but, I don't want to control the "big stuff" with it. I have a radiator with a triple fan set up. Do I run all 3 fans with one relay or 3 separate relays? Also, what is the best relay to use? I'll also be going with a relay "hot wire kit" on my fuel pump. Thanks in advance 

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What is the amp draw of your fans?  There should  be a tag on the motor housing that will tell you. The larger fans will typically require a relay for each due to the amount of amperage the fan draws. Some like to use a relay for each fan to increase reliability. If one relay fails your other fans will still function. Hella seems to be a popular relay on off road cars. The GM weatherpack style relays are solid as well. Make sure to order a couple of spares to keep on the car.

Edited by sandkist

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If I remember correctly you have a smaller motor so I’m sure you’re running 3 smaller fans. You probably can run 2 on 1 relay and the other on its own. I prefer to fuse and relay each fan on its own. Just in case one goes it doesn’t take out the other one. But I’ve seen plenty of big duals ran on 1 relay. Also not sure what a hot wire kit is. But generally with wiring the trick is to keep it simple. 

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42 minutes ago, sandkist said:

What is the amp draw of your fans?  There should  be a tag on the motor housing that will tell you. The larger fans will typically require a relay for each due to the amount of amperage the fan draws. Some like to use a relay for each fan to increase reliability. If one relay fails your other fans will still function. Hella seems to be a popular relay on off road cars. The GM weatherpack style relays are solid as well. Make sure to order a couple of spares to keep on the car.

Good advice. 

I would use 3 separate relays for 3 fans, the startup amperage for a fan is a lot for a brief moment and could possibly pop a fuse if ran through 1 relay. And if your ecm will do it, stagger the temps when they come on so they won't drop your voltage all at once. 2 fans controlled by the ecm and the third on a manual switch might not be a bad idea. On my car's fans I used on-on switches so I could let the ecm turn them on and off normally and flip the switches to turn them on manually if I  desired. 

I use Hella relays and a couple of 4 way relay centers with sealed clears cover I got on amazon, cheap and works well. The sealed and prewired relay bases are excellent too but cost a lot more per relay. 

You can treat the fuel pump just like a fan, nothing special about it. The ecm will send a ground to the relay coil and turn it on.  Maybe a little early in your build to discuss details of the wiring, but I like Blue Sea fuse boxes. For the relays, you can set up a common 12v feed for the relay coils off of a single 20a fuse, and then feed each relay's load off of individual fuses. If you have a device that sends a 12v trigger, then use the ground buss bar on the fuse box to supply the ground to the relay coil.

Edited by fortyfour

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With the fans run a relay for each. They make relays that can handle all of the fans but they wear out much faster. The real issue is the connector and wire at the relay. The heat buildup there drawing that many amps will burn up the wire. Been there done that. 

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4 hours ago, sandkist said:

What is the amp draw of your fans?  There should  be a tag on the motor housing that will tell you. The larger fans will typically require a relay for each due to the amount of amperage the fan draws. Some like to use a relay for each fan to increase reliability. If one relay fails your other fans will still function. Hella seems to be a popular relay on off road cars. The GM weatherpack style relays are solid as well. Make sure to order a couple of spares to keep on the car.

I'm not sure on amp draw. I know they are 8" fans so, I'm sure it can't be much. 

3 hours ago, jtmoney714 said:

If I remember correctly you have a smaller motor so I’m sure you’re running 3 smaller fans. You probably can run 2 on 1 relay and the other on its own. I prefer to fuse and relay each fan on its own. Just in case one goes it doesn’t take out the other one. But I’ve seen plenty of big duals ran on 1 relay. Also not sure what a hot wire kit is. But generally with wiring the trick is to keep it simple. 

I will go with a relay on each fan. The hotwire kit uses the ignition switch to trigger a relay to pull straight from the battery. A lot of guys have told me to set up my fuel pump like this...

3 hours ago, fortyfour said:

Good advice. 

I would use 3 separate relays for 3 fans, the startup amperage for a fan is a lot for a brief moment and could possibly pop a fuse if ran through 1 relay. And if your ecm will do it, stagger the temps when they come on so they won't drop your voltage all at once. 2 fans controlled by the ecm and the third on a manual switch might not be a bad idea. On my car's fans I used on-on switches so I could let the ecm turn them on and off normally and flip the switches to turn them on manually if I  desired. 

I use Hella relays and a couple of 4 way relay centers with sealed clears cover I got on amazon, cheap and works well. The sealed and prewired relay bases are excellent too but cost a lot more per relay. 

You can treat the fuel pump just like a fan, nothing special about it. The ecm will send a ground to the relay coil and turn it on.  Maybe a little early in your build to discuss details of the wiring, but I like Blue Sea fuse boxes. For the relays, you can set up a common 12v feed for the relay coils off of a single 20a fuse, and then feed each relay's load off of individual fuses. If you have a device that sends a 12v trigger, then use the ground buss bar on the fuse box to supply the ground to the relay coil.

That is true on the amp draw from fan startup. I'll need to get with John at Outfront on how many fan control leads I'll have with the new stand-alone system... Where can I find the Hella relays with the pigtails? Also, where can I find the Blue Sea fuse boxes and a battery master cutoff? 

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This is my first "non-VW" car and I'm learning a lot and taking boat loads of advice from the pro's. I know I can be annoying at times with all of the posts but, I do appreciate all of your guys help! 

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Annoying? Not at all. Keeps the forum alive. 😊

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2 hours ago, Jonesin' said:

I'm not sure on amp draw. I know they are 8" fans so, I'm sure it can't be much. 

I will go with a relay on each fan. The hotwire kit uses the ignition switch to trigger a relay to pull straight from the battery. A lot of guys have told me to set up my fuel pump like this...

That is true on the amp draw from fan startup. I'll need to get with John at Outfront on how many fan control leads I'll have with the new stand-alone system... Where can I find the Hella relays with the pigtails? Also, where can I find the Blue Sea fuse boxes and a battery master cutoff? 

The fan control leads usually open a ground path to trigger the relay. They are very low voltage and there should be no issue connecting 3 relays to it. 

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1 hour ago, SANDPSYCHO said:

The fan control leads usually open a ground path to trigger the relay. They are very low voltage and there should be no issue connecting 3 relays to it. 

The fan control signal CLOSES the circuit by either providing gnd or +12v to the relay. Whichever one it is, simply provide the opposite to the other wire on the relay solenoid. An OPEN does not allow any current to flow and is thus off.

They are very low AMPERAGE and will draw almost nothing, but they need 12 VOLTS to trigger them. 

Just trying to keep things correct.

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Sounds good guys! I'll check out Kartek for my electrical stuff. Unless anyone has a better spot?

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I've read on here in the past that Bosch is the way to go for a relay. I wired my whole car myself with John@Outfronts website layout. Thanks John! There are plenty of other electrical sites for those pieces cheaper I believe. I used info from LT1swap dot com where they referenced a website for fuse blocks, wire and relays. Worked out sweet. Good luck, keep posting and keep us posted. 

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1 hour ago, socaldmax said:

The fan control signal CLOSES the circuit by either providing gnd or +12v to the relay. Whichever one it is, simply provide the opposite to the other wire on the relay solenoid. An OPEN does not allow any current to flow and is thus off.

They are very low AMPERAGE and will draw almost nothing, but they need 12 VOLTS to trigger them. 

Just trying to keep things correct.

I was trying to explain it in a way normal people can understand. That's why I said usually. Most temp triggers or ECUs creat a ground path to switch the relay on. Yes you are correct the term in closed circuit. I'm trying to speak English and your speaking Latin if a person isn't as well versed :lol:

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1 hour ago, SANDPSYCHO said:

I was trying to explain it in a way normal people can understand. That's why I said usually. Most temp triggers or ECUs creat a ground path to switch the relay on. Yes you are correct the term in closed circuit. I'm trying to speak English and your speaking Latin if a person isn't as well versed :lol:

I'm versed enough to understand. Just not looking forward to all of the wiring and labeling! :D

Edited by Jonesin'

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1 hour ago, SANDPSYCHO said:

I was trying to explain it in a way normal people can understand. That's why I said usually. Most temp triggers or ECUs creat a ground path to switch the relay on. Yes you are correct the term in closed circuit. I'm trying to speak English and your speaking Latin if a person isn't as well versed :lol:

The correct way isn't any harder to understand. 

Like if I posted that you love BLM rangers. It's not that hard to understand, but it sure wouldn't be true.

:lol:

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3 hours ago, Jonesin' said:

Are they foreign?

Nope. Located in Minnesota USA.

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56 minutes ago, socaldmax said:

The correct way isn't any harder to understand. 

Like if I posted that you love BLM rangers. It's not that hard to understand, but it sure wouldn't be true.

:lol:

Only in the ass backwards world of electricity is closed on and opened off. Try that with a gas, liquid or a sewage tank and you'd be covered in it. :lol:

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1 minute ago, SANDPSYCHO said:

Only in the ass backwards world of electricity is closed on and opened off. Try that with a gas, liquid or a sewage tank and you'd be covered in it. :lol:

You're right, it does sound like it's the opposite of liquids. If you think of the wire like a pipe, it makes a little more sense. There are a lot of water control parts that have similar electronic counterparts. 

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Funny I just went thru the same thing.  I had the best correct waterproof bosch relays but the connectors themselves were the problem.  The trigger wire from the computer failed and the fuel pump would not run.  We made a jumper in the dunes and continued the ride.  The next day the trigger wire to one of the fans failed on the ride to Duners Diner.  

20161028_094312.thumb.jpg.5d1fb015859705e1c10d3a107c2a56ae.jpg

What I suspect is the harness was built  with little or no flexibility.   My decision was to replace it all nd eliminate future potential problems.  I bought this pre-wired waterproof relay/fuse setup off ebay.  I had done one of these bare before on another car and it takes a long time to wire them from scratch. I wasn't going to go thru that again.

20190216_131138.thumb.jpg.b5635929d8a758e9254d8a1acaeb5f8c.jpg

20190216_131149.thumb.jpg.ec2e8a4c2198cac5fd3b5facbe827065.jpg

This waterproof set-up has 5 / 30amp relays with fuses and 5 additional fused circuits for your choice .

I ran all new trigger wires to the ECU, and re-wired all new to  the Oil cooler fans, Right Fan, Center Fan and Fuel pump  (left fan comes on at start-up with the separate 30 second delay relay under the dash). I used one of the fuses for the fuel gauge sender /gauge.  The remaining circuit is still available for future use.  Took about three afternoons but everything is now sleeved & shrink wrap sealed .

I expect no more problems and I still have additional circuits available for future uses. 

20190223_120919.thumb.jpg.f254b6754d68f821a8e79953f8a0a33d.jpg

NOTE:  This picture is without the cover.

DL

20161028_094309.jpg

Edited by Dunelover

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6 hours ago, Dunelover said:

Funny I just went thru the same thing.  I had the best correct waterproof bosch relays but the connectors themselves were the problem.  The trigger wire from the computer failed and the fuel pump would not run.  We made a jumper in the dunes and continued the ride.  The next day the trigger wire to one of the fans failed on the ride to Duners Diner.  

20161028_094312.thumb.jpg.5d1fb015859705e1c10d3a107c2a56ae.jpg

What I suspect is the harness was built  with little or no flexibility.   My decision was to replace it all nd eliminate future potential problems.  I bought this pre-wired waterproof relay/fuse setup off ebay.  I had done one of these bare before on another car and it takes a long time to wire them from scratch. I wasn't going to go thru that again.

20190216_131138.thumb.jpg.b5635929d8a758e9254d8a1acaeb5f8c.jpg

20190216_131149.thumb.jpg.ec2e8a4c2198cac5fd3b5facbe827065.jpg

This waterproof set-up has 5 / 30amp relays with fuses and 5 additional fused circuits for your choice .

I ran all new trigger wires to the ECU, and re-wired all new to  the Oil cooler fans, Right Fan, Center Fan and Fuel pump  (left fan comes on at start-up with the separate 30 second delay relay under the dash). I used one of the fuses for the fuel gauge sender /gauge.  The remaining circuit is still available for future use.  Took about three afternoons but everything is now sleeved & shrink wrap sealed .

I expect no more problems and I still have additional circuits available for future uses. 

20190223_120919.thumb.jpg.f254b6754d68f821a8e79953f8a0a33d.jpg

NOTE:  This picture is without the cover.

DL

20161028_094309.jpg

This looks like a pretty stout set up. Where can I find something like this? 4 relays and 4 fuses would be perfect or 3 fans and a fuel pump

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