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Use any automotive relay without the "plug-in" style relay. Those connectors are way too small for that type of load. Use something like this and if you really want to make sure it works well, solder the wires to the terminals. Otherwise you could use one that still gives you the connector but the connections are better. Also use dielectric grease on them to keep them from corroding and causing a poor connection. If you use this type and make your own connections with the spade connectors, make sure they are crimped really well. Personally I don't like the physical crimp connections on loads like that, I like soldered connections. It may take more work and time, but rarely do you ever have a problem with a soldered connection if it's done right.
Last edited by ctuinstra; Jun 28, 2014 at 10:41 AM.
The relays in the link don't look anything like the photo. Yes they are automotive relays in the typical style, however the pins on the relay in your car are very small and narrow compared to the spade pins shown in my photo.
What is happening is the very small and poor connection of the PINS is causing them to heat up from the resistance. It's not the relay itself inside, but the pins are the problem. Even though the relay is rated for 40amp, the connectors don't seem to be holding up to the current.
If you have more of those relays, try soldering the wire directly to the pins and don't use the quick-connect.
Take a look at the high speed relay on your HVAC blower motor, or better yet go to your parts house and ask for one off an old Pontiac/GM from the 70's.....
and solder all wires directly to the relay tabs, that's what I do....
been that way for almost 20 years now on my '72....
12ga is what I had laying around the garage so it got used
You may be O.K with the wiring that you have--I just thought I would mention the heavier 12V "supply wire".
I'm referring to the relay terminal that receives constant 12V power...it "gets" the heaviest wire. The connection that sends 12V directly to the electric fan gets a wire similar in size to the existing fan wire. The relay terminal that gets the 12V signal from the temperature switch to "switch on" the relay when operating temperature is exceeded, gets a wire similar in size to the fan motor wire.
Sorry about the poor explanation from the rookie/me.
From experience....and taking notice on what GM does on the new Corvettes. That I personally use the relays from GM for the 1989-1996 cooling fans and other things.
The terminals in these relays and connectors are large...thus can carry the amp load. The cooling fan for the C5-C6 are even larger...and trying to figure out how to incorporate this system in....but that is something else.
And I always err on the side of caution ( always trying to prevent an electrical fire) and test the circuit to actually see how many amps it is requiring to operate. I then figure in my length of wire to get power to the relay and to the fan and adjust its gauge accordingly. Because a wires efficiency/effectiveness does drop the longer the wire is in regards to the amp load needed. I usually go one size larger and a serious multiple strand wire also....which I get from Waytek.
I bought a wiring harness from Jeg's for my dual electric fan setup. It has separate relays and circuit breakers for each fan, so a failure of one will not cause the other to stop working. Very good instructions made installation a breeze. The biggest problem was in deciding where you were going to mount all the components to keep them dry as much as possible.
I use the cole hersee 24059 marine type solenoid that kacyc3 shows above. I use them for coolong fan circuits and electric fuel pump circuits. Easy to wire larger gauge wires with the threaded terminals and you can get them on sale fron amazon for about $9 each. Lot of marine shops get $25- 40 for them. Quality solenoid/relay for sure.
I use the cole hersee 24059 marine type solenoid that kacyc3 shows above. I use them for coolong fan circuits and electric fuel pump circuits. Easy to wire larger gauge wires with the threaded terminals and you can get them on sale fron amazon for about $9 each. Lot of marine shops get $25- 40 for them. Quality solenoid/relay for sure.
wish i had known that so i didn't have to pay $35 for the one in the pic
From experience....and taking notice on what GM does on the new Corvettes. That I personally use the relays from GM for the 1989-1996 cooling fans and other things.
The terminals in these relays and connectors are large...thus can carry the amp load. The cooling fan for the C5-C6 are even larger...and trying to figure out how to incorporate this system in....but that is something else.
And I always err on the side of caution ( always trying to prevent an electrical fire) and test the circuit to actually see how many amps it is requiring to operate. I then figure in my length of wire to get power to the relay and to the fan and adjust its gauge accordingly. Because a wires efficiency/effectiveness does drop the longer the wire is in regards to the amp load needed. I usually go one size larger and a serious multiple strand wire also....which I get from Waytek.
DUB
Here are the relays that are in my 1974, and the ones DUB is talking about.
Been using this 50 amp bosch relay and 50 amp circuit breaker for 4 years.... Fan is a Lincoln MK8 fan that pulls 40 amps at start up and cycles with the AC compressor....Never had a problem with it or the relay setup... I definitely recommend this relay..
