Electric Fan Wiring... Thoughts... Opinions

[Slammed84]

Originally Posted by nekkidhillbilly

on my 01 i used just a fuse tapper under the hood for a key. hot source went to batt. ground went to factory ground had to cut the ac wire solder them in. i think though the 80s trucks have it all under the dash still could just wire through one of the groments and use a fuse tapper in the block.

Fuse Tapper???? WTF???

[Slammed84]

One of these? I've been working on cars for the better part of 15 years and I have NEVER seen one of these, WTF!!!!????

[Slammed84]

So I mocked everything up to see how it would fit.

The temp switch will work well on the drivers side. However I'm a bit worried about the temp gauge connector being so close to pass. side header. My only option is to get a different bushing to directly connect the gauge to cylinder head. As you can see there is a second bushing in between them because the temp gauge threads are smaller than 3/8 NPT. I think it will be okay if I zip-tie it out of the way but I am curious as to whether it will mess with the temperature reading on the gauge.

I'm thinking about mounting the relay next to the junction box on the firewall, would this junction box be considered a fused source? It is powered up by a hot wire that has a fusible link, so.....????

[gmachinz]

That junction will work for power to your relay. As for the proximity of the switch wire to the exhaust, that Calterm type plastic connector won't like the heat and will distort over time. The wiring I doubt is j1128 spec so it isn't designed for resisting underhood heat....especially so close to the exhaust. Will the setup work? Sure but for how long is the question. If that switch is a 180 degree switch mounted in the head, once the fan comes on, it'll likely never go off until you turn the engine off. Typically, cylinder head coolant passages are about 15-25 degrees hotter than an intake coolant passage-I would suggest running a 225-230 degree switch in the head or, relocate the one you have to the intake.
Keep in mind that a cheap relay used for allowing a fan to run for long periods of time can overheat the contacts within the relay coils and not let it release when it should-that's why Flexalite controllers are imo JUNK. They overheat too often and remain running when they shouldn't. This is why I suggest swapping out your relay for a HD diode and resistors equipped one. Not only are the contact materials able to resist overheating much better, but the diode prevents any spiking when the fan shuts off. Combined with a resistor, its a gradual shut down of the relay-which is a good thing.

[nekkidhillbilly]

Originally Posted by Slammed84

One of these? I've been working on cars for the better part of 15 years and I have NEVER seen one of these, WTF!!!!????

used them many times.

[nekkidhillbilly]

i mounted the controller right to the fans. its close to the batt is a good ground location on the core support.

[Slammed84]

Originally Posted by gmachinz

That junction will work for power to your relay. As for the proximity of the switch wire to the exhaust, that Calterm type plastic connector won't like the heat and will distort over time. The wiring I doubt is j1128 spec so it isn't designed for resisting underhood heat....especially so close to the exhaust. Will the setup work? Sure but for how long is the question. If that switch is a 180 degree switch mounted in the head, once the fan comes on, it'll likely never go off until you turn the engine off. Typically, cylinder head coolant passages are about 15-25 degrees hotter than an intake coolant passage-I would suggest running a 225-230 degree switch in the head or, relocate the one you have to the intake.
Keep in mind that a cheap relay used for allowing a fan to run for long periods of time can overheat the contacts within the relay coils and not let it release when it should-that's why Flexalite controllers are imo JUNK. They overheat too often and remain running when they shouldn't. This is why I suggest swapping out your relay for a HD diode and resistors equipped one. Not only are the contact materials able to resist overheating much better, but the diode prevents any spiking when the fan shuts off. Combined with a resistor, its a gradual shut down of the relay-which is a good thing.

Unfortunately I have no choice but to put the temp switch in the cylinder head. Someone put a plug in the second coolant passage in the intake and must have glued it in with some loctite because I have tried everything to get it out. I have tried a long handled ratchet with a cheater bar and also my impact. It is an allen head plug so it's going to end up stripping out if I try too hard.

Any recommendations on a good relay that I can just buy over the counter?

I really don't want to go scour junkyards for a relay if I don't have to.