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painless cooling fan wiring question/opinion

does the control side of your relay wiring have a diode ? If not the relays won't last. Check the amp draw on your fans when hot.
 
Link isnt working. Are you running two fans through one relay?
If your efi will control the fans you dont need any kits. You need circuit breakers and relays for each fan, current matched ti fan. Full battery voltage to breaker, then to relay. Key on power to each relay. Efi trigger to each relay, and each relay to fan power. Each fan to good ground. Super simple, super reliable.
 
There is a relay for each fan , it’s an old painless kit they no longer sell.
 
I have the painless kit you linked running dual flexalite 15”s. I am triggering it with my megasquirt ecm instead of the coolant sensor they send. Regardless, it’s been on there a few years and has never even flinched.
 
Lets look at this from a slightly different angle.
When you say its eating relays, assuming the wires are not so old they have grown teeth, what is failing on the relays?
Do they stop clicking, do they click but the fan does not come on, or do the terminals get hot and melt?
Have you opened one to see what is wrong, or do you have one you can open? Before you can fix a problem, you need to find out what the problem is.
 
Fordum said:
Lets look at this from a slightly different angle.
When you say its eating relays, assuming the wires are not so old they have grown teeth, what is failing on the relays?
Do they stop clicking, do they click but the fan does not come on, or do the terminals get hot and melt?
Have you opened one to see what is wrong, or do you have one you can open? Before you can fix a problem, you need to find out what the problem is.
Click to expand...

that’s a good point, if multiple relays are failing, you’ve got some bad wiring or something else weird going on.
 
Fordum said:
Lets look at this from a slightly different angle.
When you say its eating relays, assuming the wires are not so old they have grown teeth, what is failing on the relays?
Do they stop clicking, do they click but the fan does not come on, or do the terminals get hot and melt?
Have you opened one to see what is wrong, or do you have one you can open? Before you can fix a problem, you need to find out what the problem is.
Click to expand...
the relay melts
 
Perfect. Now we know what the problem almost certainly is, and how to fix it.
There are two pins on that relay that carry the same amount of current. Since only one is melting, the problem is that connection.
The spring loaded contacts inside that socket have gotten weak or tarnished to the point where they are not making good contact.
A bad contact causes a high resistance connection, which generates heat. That causes the contact to get worse and generate more heat until everything fails.
The cure is a new contact.
Since its a socket, its hard to replace just one, so the best solution is to replace the socket. You might try contacting Painless to see if they would sell you two new sockets, but those style sockets are very common. You should be able to find them lots of places.
I'll scout around in a little while to see what I can find.
Unless you have the special crimper that is used to attach the contacts to the wire, it would be easier to use some prewired sockets and just splice the wires. Of course, the splices have to be very good. With these currents, I would consider a soldered splice with good high temp insulation rather than a crimped splice.
A crimped splice can be as good as a soldered one, but it takes a good crimper and is harder to get right.
The downside, is that you will have to replace the relays also. Once the contact gets hot enough to change color, its always going to cause a problem.
If they were extremely expensive, you could try cleaning the contact, but the way to be sure is new relays in new sockets.

Its possible that the bad contact is inside the relay where the contact attaches to the relay, but that is very unlikely since new relays do it.
The socket is the common factor.

One thing to remember, is you nailed it when you said your wiring was eating relays.
 
If relays are correct amperage, you have a wiring issue as said. Both relays and both fans need good grounds. You should have fuses or circuit breakers feeding relays
 
thats why i want to replace the entire thing its over 10 years old tired of patching or replacing a whole run of that wire and it does it again in three months.
i also ordered the 30117 kit above
 
and if it eats em after this replacement ill replace the fans, thats going to sting the pocket book
 
It seems obvious to me that your fans are drawing more current than the relays can handle. Are they 20A relays? You can put a fuse in there and protect the relays that way.
 
There seems to be two different rated relays out there.
30/40 amp, and 60/80 amp. Judging from your picture, that looks like a 30/40. But there is no good frame of reference to tell how large the terminals are.
Even if you replace the harness, if the relays are the 30/40 ones, you might consider an upgrade.
Most of the relays are dual rated, since a set of contacts will handle different amounts of current depending on if they are NO or NC.
This one just says 80 amp, period.
https://www.amazon.com/Ehdis-Truck-...80+amp+relay+5+pin&qid=1611501040&sr=8-1&th=1
They seem to be just standard heavy duty relays.

These claim to be waterproof.
https://www.amazon.com/PACK-AMP-Wat...7XC6KHD3/ref=psdc_15733511_t1_B01KFKEHMG?th=1
But they come in a 5 pack.
Of course, if you bought the 5 pack, then you would have spares of everything which you could then put someplace "where I will know right where it is....."
Which, of course, means you will never see them again....
Check your melted relay and see if you see an amp rating.
Also, note that the 30/40 and the 60/80 use different size contacts, so they have to use their own type socket.
In other words, you can't plug the heavier relay into to the lighter duty socket.
 
Aha, I went back and read the description of they harness, and they are 40 amp relays.
Drat, company, I'll post more later
 
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