relay?

[harshman]

I just installed my aluminum radiator, Derale dual electric fans, and fan controller. Worked great for a while until I melted the relay. I think it was a 30-35 amp relay. So…. What now? Do any of you guys know of a good fan control with a awsome relay?

[chevymike]

I put a Bosch (IIRC) 75 amp relay in. You should be able to swap out your melted on with one of these and keep your controller. I used a Painless fan switch (in the head) plus a manual override switch inside. So far, so good.

[gmachinz]

Mike, I don't suppose you could shoot me a schematic of how you wired your system could you? It would be greatly appreciated! [email protected]

[chevymike]

Here you go. Hope this answers your questions. Sorry I didn't remember the pin numbers on the relay.

[Midwest Performance]

Out of curiosity what kind of controller are you using?

[harshman]

Out of curiosity what kind of controller are you using?

Derale. I talked to 'em last night and was told that although their controller is set up to control the second fan, the fans that I have require another relay (50 amp draw) - aka another controller. I installed the second one this morning and they seem to be working fine. I’m a bit irritated that I spent $50 for each controller just because of the size. Live and learn.

[gmachinz]

On your diagram Mike, I have one question-the leads you show coming from one side of the coil to both a dash switch and a thermo-switch....does the one to your dash switch act as a manual override? Like an on/off switch? Reason I ask is because while I understand your schematic, the one I was going to use from Imperial uses a thermostatic controller w/probe and the directions on it say to run an ign. lead to one side of it and run the other lead directly to the fan. Now, obviously I do not want 50+ amps flowing through my controller, so I am using a relay to "turn on" the fan, while the switch side of the controller will "turn-on" my relay. So, put my mind at ease and tell me you wired a "dash switch" to act as an override. -Jabin
"he who stands on toilet is high on pot"

[CarlC]

There's info on my website for relays and temperature switches used on a Mark VIII application. Same would apply for you.

[chevymike]

gmachinz: Yes the dash switch is a manual override. If I turn it on, it will start the fan and will stay running until I turn it off or turn the key off (system runs off of switched ingition). If the fan switch is off, it runs in auto mode using the thermo switch to control the fan on/off times.

I don't know how your controller wants to be run. I my case, I am using the thermo or regular switch to control when the relay coil sees ground. Positive power to the relay coil is coming from a switched source which is why when I turn off car, the fan will stop. Didn't show that in the drawing. Sorry.

Hope this helps.

[gmachinz]

Okay, so I have my wiring system designed just as yours is, then. Now, that means you basically have your controller on via an ignition source, which then trips the relay to power your fan, right? So your controller is wired ahead of your relay, correct? I have it then-time to get to soldering! -Jabin

[chevymike]

When you say controller, do you mean the thermo switch? All I have in the system is a DPDT switch, thermo switch in the head, a 75 amp relay, the fan and wires. No other items.

Basically switched 12 volt goes to the + input on relay coil. - input on relay coil goes to the thermo switch AND the DPDT manual switch. When the thermo switch reached 200* it becomes a ground for the relay and closes the relay, which turns the fan on from the high current side of the relay. The DPDT switch has a - wire from the relay (like the thermo switch). It goes into the middle contact. On one set of terminal on the switch, it goes to ground. When I turn on the switch, it creates a ground path and closes the relay, hench overriding the thermo switch.

Make sense? I am not sure what you mean by a "controller".

[TurboLark]

I just used a dual relay setup for the Mark 8 fan. Put the relays side by side and connect the same wires together. Splits the load, and much cheaper to replace a 30amp relay than try to find on big one.

[gmachinz]

Well, the controller I looked at is a thermostatic type with a probe. But on your set-up, your switch in the head goes to what terminal on the relay-#86? And that terminal shares the lead going to your manual override as well? Or is it terminal #85 that goes to your switch in the head? I guess that would make more sense. Maybe just label (30,85,86 and 87,87a) where each wire on your relay routes to. I guess I wnat to eliminate the controller idea until I ee the one from DCcontrols first. -Jabin

[chevymike]

OK, I made up a new drawing. I had to look up the relay contact numbers. I added them and the exact path everything is taking. Let me know if you still have questions.