Replaced clutch fan with electric fan

[Overboost]

Pin 85 is ground and pin 86 is the 12V trigger on all the relays I work with. Not sure where you got that pin out?

[workingonit]

It's shown that way in the attachment, and here's another with the same. 30 is main source of power (high amperage input, battery), 85 is the trigger (lower amperage input, switched power), 86 is ground (for the relay itself), and 87 is the high amperage output (to power the high draw accessory). That's the way it's been my whole adult life, used in workplace and automotive projects I've done!

[Overboost]

Pin 85 and 86 just charge the coil so I guess you can hit it either way. I have always followed the German logic of 85 being ground.

[workingonit]

Like they used to say around here, "same difference"; mox nix!

[bcredliner]

The fan thermostat is the control source. I have an inline fuse for fan draw. Power source is charging post. Has been wired that way for several years, no issues other than controller stopped working so had to replace it. I don't see a controller in the parts pictures. The one I have is a dial that I can turn for hotter or cooler fan start. There should be a how to that I did way back when.

[workingonit]

Originally Posted by bcredliner

The fan thermostat is the control source. I have an inline fuse for fan draw. Power source is charging post. Has been wired that way for several years, no issues other than controller stopped working so had to replace it. I don't see a controller in the parts pictures. The one I have is a dial that I can turn for hotter or cooler fan start. There should be a how to that I did way back when.

The Derale 16738 fan controller (in the picture previously shown) uses the thermostatic probe/sensor/switch (semantics!) as the only on/off control if non-switched power is used to trigger the relay. It is pre-set to turn on at 180F degrees and off at 165F degrees. Non-adjustable.

I want a little more control over the system; using

• 1) a switched power/trigger, and
• 2) a manual override switch,

Why?

• a) to regulate when and for how long the thermostatic switch is active,
• b) to not let the system run wild and drain the battery, and also
• c) to delay the fan coming on if quicker heat is needed on a very cold day (not really a problem though in Texas, usually).

There's a warning note in the kit's instructions about possibly draining the battery; it's my primary reason for finding an underhood switched power source.

[bcredliner]

The fan I have doesn't run that long after I shut it off. Two or three bursts of about 30 seconds or so and it doesn't come on again. No problem with my battery. I'm getting 5-7 years out of batteries. Not suggesting you should wire it the way I have just some input and encouragement from someone that has had an electric fan for several years without any problems. They're great.

Why does it shut off at 165F?

[oldskewel]

Makes sense on the manual override. That's what I'd want too. On / auto / off

I also would be concerned with battery drain after the car is off. Here's an idea for that ...

Most circuits in the car are switched off after 16 minutes when the car goes to sleep (I think key out and doors all closed triggers that). So if you found one of those circuits and ran a wire from the fuse box through the firewall into the engine bay, and used it to turn a relay on, to unswitched engine bay power, that would give you an extra safety against running down the battery. Of course it would make sense to design this and your on/auto/off control together.

If for some reason the controller or sensor malfunctioned or you parked on top of a volcano, even if the fan would want to stay on, the sleep mode would turn it off after 16 minutes.

[workingonit]

Originally Posted by oldskewel

...I also would be concerned with battery drain after the car is off. Here's an idea for that ...

Most circuits in the car are switched off after 16 minutes when the car goes to sleep (I think key out and doors all closed triggers that). So if you found one of those circuits and ran a wire from the fuse box through the firewall into the engine bay, and used it to turn a relay on, to unswitched engine bay power, that would give you an extra safety against running down the battery. Of course it would make sense to design this and your on/auto/off control together.

If for some reason the controller or sensor malfunctioned or you parked on top of a volcano, even if the fan would want to stay on, the sleep mode would turn it off after 16 minutes.

Originally Posted by workingonit

The optional override switch(also 85), will be tied to the cigarette lighter (which powers off, "sleeps", after 16 minutes, so if I choose to, I'll switch it on to let the fan run 16 minutes after the engine's off.

I was going to use sleep mode to be sure that my on-off manual override turned off if I forgot to, or intentionally left it on for post-drive cooling. I'm still looking for an underhood switched source.

[workingonit]

I received my 16" Flex-A-Lite 238 fan late yesterday afternoon, and started to install it. The original mechanical fan came off easy; I didn't even use the tools bought specifically for fan removal, just a tap on the 1 1/4" wrench did the trick. I tried to use the push-thru plastic rods that came with it, to fasten the fan to the radiator, but they were too large in diameter to push thru.

I found another set I had bought before, smaller in diameter; they would fit in between the fins OK, but there was no room to put the locking piece on the other side, since there's only about 3/4" space between the radiator and A/C condenser. So, I went to Home Depot to buy two 36" long 1"x1/8" aluminum flat bars, to make a frame to mount the fan on the shroud.

I used my Wen (Dremel substitute) to make slots in four spots in the shroud, placed just-so that the fan an bars will not contact the radiator fins, but remain about 1/8" shy of touching. The shroud can slip back into its' original position, with the fan centered in the shroud opening. I'll do that today, while I'm running wires thru the firewall (if the part comes in the mail).