Electric fan: Switch or controller?

[rang-a-stang]

This weekend I am going to pick up a Ford Contour fan. Looks like most folks on here wire it in with the Flex-a-Lite controller but that's $130+. My old (don't laugh, it was awesome) Geo Metro had a coolant switch that closed at 215degrees and opened at 205 degrees. Those switches are $25 new.

Any reason why one of those switches wouldn't work wired up to a relay?

[SJTD]

That's what I'd use. Might look for a different temp range unless that's what you want.

Is it a two speed fan? If so you can run two switches/relays.

[wiley-moeracing]

I used a switch, relay set up out of a volvo 60 I believe

[tenoverthenose]

When I hooked up my electric fan that's what I did. I used a wire that had power when the engine was running going through a coolant switch as a trigger for the relay. I've never had a problem with it operating.

[rang-a-stang]

Fantastic feedback, gentlemen! I appreciate it!

So this morning I was poking around on the interwebs looking for a good relay bracket and stumbled upon these 2 posts:

https://www.cherokeeforum.com/f67/taurus-fan-volvo-2-speed-relay-how-214815/

http://www.therangerstation.com/tech_library/volvo_electric_fan.shtml

Funny because therangerstation.com is one of the first forums I was a member of back in the late 90's early 00's (it's where my handle comes from) but I digress.

This looks like a good way to do it! I see these Volvos in Southern California wrecking yards fairly often. Is that what you had Wiley-Moe?

[wiley-moeracing]

yes

[rang-a-stang]

Headed out to the wrecking yard out here and scored a Volvo set! Woo Hoo!

I have soooooo many projects lined up for when I get home!

[ZackN920]

Do you actually feel any power difference when ya do this mod?

This is one of those mod's that just doesn't seem too worth it, especially if things are working just fine as they are. That, and it puts added strain to an already weak electrical system. idk though...never done it.

[rang-a-stang]

I don't yet. I doubt I will feel a difference but the reason I am doing it now is because I have a BullTear serpentine set up waiting to go on, I am removing my smog pump for my EFI install, adding new relays for my headlights and off road lights, and I figured if the front of my engine is coming apart and all this new wiring is going in, might as well stick a fan in there. The Volvo relay was $6 and I expect to get a wrecking yard fan for about $30 so its "cheap". I probably wouldn't add it on its own since it seems to cool fine right now.

[ZackN920]

hmm, but I wonder what kind of a load that will put on the electrical system. After you add more lights and the fans, you may need to upgrade the alternator to handle the loads, if you hadn't all ready.

Heck, I could probably upgrade from where I'm at now, and I already got a 105amp. I end up in the red zone, if I have the lights and a/c on when sitting at idle. I haven't actually measured at the battery though either(to really find out where it's at).

[rang-a-stang]

I don't know yet (how much stress on my electrical system)! We'll see. I am not opposed to running a new alternator if I need to. I guess I'll cross that bridge when I get there.

[rang-a-stang]

There is a slick BMW dual temp switch for $11 on Rockauto with another ~$10 in connectors, pins, etc.

First switch closes at 195° and second at 210°. I have a 195° T-stat so I assume I will want to install the switch on the warm side of the radiator (upper driver side)?

I just bought a used Edelbrock intake that comes with a t-stat housing that has a little bung on the top of it. Would that be a good place to redrill/tap/thread and stick the switch? Looks like this one (my current TStat housing does not have that bung):

I also plan to set my A/C signal to the low speed relay and will have a manual bypass that will enable both fans.

[77Deepj20]

It would be more ideal to have the switch closer to the head, but it will work there. Mines in the upper radiator hose, works fine. Its just a basic grounding switch that operates a relay to power the fan. My second fan is powered from a toggle switch for backup.

[Crankyolman]

I had my fan clutch go bad and had trouble finding a short enough clutch so for a while I ran nothing but an electric fan. Once I got a new fan clutch from BJ's I replaced the switch so the electric fan comes on if the engine starts to get hot. I don't think the thermostat housing is the ideal place to put the switch but that's where I put mine and it works fine.

I'm pretty sure the relay kit I used was this one

https://www.amazon.com/Partshow-Degrees-Electric-Thermostat-Temperature/dp/B076JHGK2T/ref=sr_1_2_sspa?ie=UTF8&qid=1509932425&sr=8-2-spons&keywords=electric+cooling+fan+relay&psc=1

and the switch by itself is this one

https://www.amazon.com/gp/product/B015PGEZKO/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I run a 180 degree thermostat so I have the fan shut off at 185. They sell other switches for other temps as well.

[Mikel]

In many engines the thermal switch is in the water inlet coming from the radiator, not in the engine itself.

The idea is that if the radiator is getting airflow, cold coolant will flow into the engine. The moment hot coolant starts going into the engine, the fan turns on.

I think it is a better way to control the fan than waiting for the engine to get hotter.