30 Amp Relay

GKK · Jan 10, 2011

I'm wiring up a 30 amp relay for my 16" electric radiator fan. This relay has 4 spade terminals on the bottom...

#85 that goes to the ground
#30 power lead from the battery or fuse panel
#87 power lead from the relay going to the fans
#86 power from the ignition for the trigger switch

My question is can I get the power for #30 and go thru my toggle switch and connect to #86, I see really no difference. Both are hot, one is coming from the ignition and the other is coming from the fuse panel basically from the ignition anyway.

For those who have wired an AAW 500434 I have cut the Pink wire going to the fans and wired in a relay at the firewall under the dash.

thanks GKK

fiddlerpin · Jan 10, 2011

I brought my power for the fan directly from the battery by way of a 25 amp fuse. I am using a Rib relay (relay in box). Available at graingers or refrigeration supply houses. Their coils are A/C or D/C 10 to 30 volts. You could do it the way you described as the coil of the relay should draw very low amps to pull in the fan contacts. The only problem is the wire size cause it's operating your fan. Should be at least a 10 ga. wire. You will have to run a smaller wire maybe a 16 ga. and install an inline fuse before your toggle switch. I ran my control voltage from the red circuit fused to an adjustable thermostat set about 170 degrees. Grounded other ends of relay coil and fan motor. My fan will run if needed even with the ignition off.

This allows the radiator and engine to cool down some in the hot summer months just like the new cars do. Won't drain my battery cause it doesn't run that long. Jim

acardon · Jan 10, 2011

Terminal 30 should be connected to unswitched/constant power so the fan current doesn't have to go through the ignition switch. If you connect 86 to 30 and accidently leave the switch on, it will kill the battery in a short time. If you put a temperature switch in the manifold to turn the fan on at a certain temperature, connect 85 to the temp switch and it will be automatic.

56Mark · Jan 10, 2011

GKK said:
I'm wiring up a 30 amp relay for my 16" electric radiator fan. This relay has 4 spade terminals on the bottom...

#85 that goes to the ground
#30 power lead from the battery or fuse panel
#87 power lead from the relay going to the fans
#86 power from the ignition for the trigger switch

My question is can I get the power for #30 and go thru my toggle switch and connect to #86, I see really no difference. Both are hot, one is coming from the ignition and the other is coming from the fuse panel basically from the ignition anyway.

For those who have wired an AAW 500434 I have cut the Pink wire going to the fans and wired in a relay at the firewall under the dash.

thanks GKK

What you are proposing defeats the purpose of the relay. You would just be turning the fan on with the toggle switch and the relay is not doing anything. It would work, but you are running a lot of current through a toggle switch. The purpose of a relay is to allow you to control a large current with a very small amount of current. I wouldn't run all of the power through a toggle switch; I would pickup the power for #30 as close to the fans as I could and put the relay close to the fans, then you can run the small control wire (#86) through a temperature controller, toggle switch, AC trinary switch, or what ever.

Rick_L · Jan 10, 2011

You are not completely defeating the intent of the relay by getting the power at terminal 30 since only the power needed for the relay coil will go through the switch.

But I would wire the power for the relay coil to a wire or terminal that is hot only when the key is on. That way the fan will only run when you are driving, as acardon pointed out.

GKK · Jan 10, 2011

Rick_L said:
You are not completely defeating the intent of the relay by getting the power at terminal 30 since only the power needed for the relay coil will go through the switch.

But I would wire the power for the relay coil to a wire or terminal that is hot only when the key is on. That way the fan will only run when you are driving, as acardon pointed out.

Actually #30 is on the ACC side of the ignition switch in the AAW wiring harness. When the ignition switch is "on" the fan is on when the Ignition switch is "Off" the fan is off. I just wanted to be able to turn the fan "off" when the ignition is in the "on" position using the relay instead of just a toggle switch handling all of the power..and get the power from the #30 power lead. thanks gkk

acardon · Jan 10, 2011

GKK said:
Actually #30 is on the ACC side of the ignition switch in the AAW wiring harness. When the ignition switch is "on" the fan is on when the Ignition switch is "Off" the fan is off.

That was my point, it's NOT a good idea to run a 20 or 30 amp fan through the accessory contacts of the ignition switch. It wasn't designed for that much current. The accessories put enough load on the ignition switch. Connect #30 to the starter post or battery, and if you have the update wiring, run the orange fan wire through your switch to #86.

Rick_L · Jan 10, 2011

Wiring it to the ACC terminal on the switch would indeed defeat the purpose of the relay.

GKK · Jan 11, 2011

Alright guys lets just forget about the relay for the moment. I'm not a wiring expert but please explain to me the following.... and these instructions are from the AAW wiring instructions.

The picture depicted on the fuse panel directions shows a 30 amp fuse for a fan. The instructions read...electric fan power "Feed" to fan relay. To me this is the hot wire that will carry the load . It says nothing about a trigger switch. How many amps does it take to trigger a 30 amp relay?

acardon · Jan 11, 2011

I agree that the AAW kit should NOT have a 30 amp fuse on that circuit. A 5 amp fuse would be plenty.
The fact remains and was confirmed by Donny at AAW that the fan current should NOT go through the ignition switch. Trigger the relay with the orange wire and get the fan power (terminal 30) from a constant source.

GKK · Jan 11, 2011

acardon said:
I agree that the AAW kit should NOT have a 30 amp fuse on that circuit. A 5 amp fuse would be plenty.
The fact remains and was confirmed by Donny at AAW that the fan current should NOT go through the ignition switch. Trigger the relay with the orange wire and get the fan power (terminal 30) from a constant source.

Now that makes sense to me...I have also inquired with AAW, Donnie, about the same thing. I wonder how many have wired the circuit the way it indicates? I think the accessories bundle does the same thing therefore I will need to rewire my fuel pump as well since I had it wired into the accessories as a "Fused" 12 volt feed". Thanks acardon this could have ended in a bad way if I had not inquired. GKK

Rick_L · Jan 12, 2011

If you think about what should be there - you need your relay coil on one fuse - it could be shared with other relay coils or other low draw components - and you need a separate fuse on the main power that's wired to terminal 30.

Since the typical fuse panel isn't going to accomodate the high amp power circuit for the fan, just fuse it separately. It's an excellent place to use a maxi fuse or something similar.

This would be true for just about anything you run with a relay.

I think that's something that is not emphasized enough in the literature that comes with most wiring/fuse panel kits. They aren't anxious to admit that you didn't buy enough materials to do the job.

GKK · Jan 12, 2011

Rick_L said:
If you think about what should be there - you need your relay coil on one fuse - it could be shared with other relay coils or other low draw components - and you need a separate fuse on the main power that's wired to terminal 30.

Since the typical fuse panel isn't going to accomodate the high amp power circuit for the fan, just fuse it separately. It's an excellent place to use a maxi fuse or something similar.

This would be true for just about anything you run with a relay.

I think that's something that is not emphasized enough in the literature that comes with most wiring/fuse panel kits. They aren't anxious to admit that you didn't buy enough materials to do the job.

LOL...They aren't anxious to admit a lot of things apparently. sent you a pm.

acardon · Jan 12, 2011

On the AAW update harness, there are a lot of fused ACC circuits that do not go through the ignition switch. The power seat, power window and power door locks are some of the high current outputs that are constant power and are powered by the red wire from the starter solenoid post through a fuseable link.

GKK · Jan 12, 2011

acardon said:
On the AAW update harness, there are a lot of fused ACC circuits that do not go through the ignition switch. The power seat, power window and power door locks are some of the high current outputs that are constant power and are powered by the red wire from the starter solenoid post through a fuseable link.

I wonder what the fuseable link is rated at?

That's correct... I think what I'm going to do is run a #8 from the battery to a lug post under the dash, the ones that you can get from Summit. Then from that I could pull what I need. But it would be simpler comming from the harness as you stated which is a very good idea.

GKK · Jan 12, 2011

This is my plan...I'm going to use the orange wire for the trigger and change the 30 amp to a 5 amp fuse. Then come off one of the accessory connectors that are battery fed for the "feed wire" for the relay and do the same for my fuel pump. That should solve the problem. Thanks GKK

30 Amp Relay

GKK

fiddlerpin

acardon

56Mark

Rick_L

GKK

acardon

Rick_L

GKK

acardon

GKK

Rick_L

GKK

acardon

GKK

GKK

Top Contributors this Month

Recommended Communities