Switched Power Source...

[CJJ67]

I want to find another way to wire my elecric fan and other things under the hood without going all the way to the fuse panel inside the cab. So I guess my question is can I tap into the wire that's marked bat. on the HEI with a fusable link and use that as a switched power source? Or can I tap into the wire on my starter with a fusible link and use that as a switched power source? I'm not crazy, I just don't know the answer. Thanks for any help that you can give me.

[Billla]

Why not just run one line from the cab to a fuse block like this one:

http://store.summitracing.com/partde...5&autoview=sku

[CJJ67]

Thanks for the help Billla, but I was trying to find a way to do it without spending money, especially this month (santa time). I have a new wiring kit but I don't want to use it until I finish my body work this summer. But for now I was wondering if I could use the HEI or hot wire to the starter solenoid.

[Boog]

I don't think tapping into the HEI power wire is a good idea for an electric fan power source. The fans draw a lot of power and the HEI needs a solid 12 volts to run right.

[CJJ67]

Thanks Boog, thanks why I'm asking, I didn't know that. So now that leaves me with the solenoid wire to the starter or the brown wire to the alternator. Learning as I go.

[Billla]

No money is cool...but I still don't understand why you don't want to just run a line from the ignition unfused spade in the cab. It's the same price as taking it from another source...?

[CJJ67]

Billla, you're the man/person...I didn't know that that was the a switched power source. Actually I had no idea what it was used for. I thought that I had to take the power from something that the ignition turned on. Since it is unfused, that is why I need to include the 30a fusable link? Oh yeah, since there are two spades, I only need to use one, right? I'm going to work on it right now. Many, many, many thanks and Merry Christmas.

[Billla]

My bad completely - I should have done the seek first to understand thing Yes, you just need to use one of them, and you do want a heavy gauge wire (red) and an inline breaker or fuse.

For future reference/searches, here's the labeled diagram provided by a board member:

[Longhorn Man]

I used a relay, triggered by the ignition unfused spot. I ran an electric fuel pump, Aux cooling fan, and an HEI off of one relay, with no problems whatsoever.

[Andy4639]

I ran a wire from the A/C switch on the back side of the air box inside the cab. It's the switch the cable operates when in A/C mode. This sends power to the relay at the fan and turns the fan on just when the A/C is on. It doesn't need a fuse because the fuse is at the box.

[LONGHAIR]

I'm with Andy one the relay. It allows you to "switch" it on/off by a smaller wire and only carry the load on a shorter, heavier wire, that is closer to the source and the fans.

[Billla]

Originally Posted by Longhorn Man

I used a relay

Always a good idea.

[CJJ67]

Got everything hooked up and the fan kinda works. The relay clicks and the fan comes on for about 2 seconds, clicks off for a couple seconds and clicks on for a couple seconds and repeats the cycle until I cut the engine off. The engine gets pretty hot so tomorrow after work I'll mess with it some more. Again, thanks for all your help and patience.

[CJJ67]

Worked on the fan and I think that I either have a bad thermo switch or a bad relay. The relay clicks and the fan comes on for about 2 seconds, clicks off for a couple seconds and clicks on for a couple seconds and repeats the cycle until I cut the engine off. The fan barely spins and the engine over heats. I jumpered the fan to the battery and it works fine. Tomorrow I'll start replacing parts.

[CJJ67]

This is my last attempt at bugging you's about this fan install. Here goes. I keep blowing the fuable link (use to be the circuit breaker) every time the temperature switch tells the fan to come on. However, with the engine still hot and turned off, I've replace the fuse, turn the ignition switch on, relay clicks once and the fan comes on and cools down the engine beautifully. This is my third temperature switch and 30/40amp relay.

This is what I've done to fix my problem: I've moved the switch from the head to the intake, replaced the wiring (all), with a test light, checked the wiring at the fan and switch for ground and checked the switch for ground, both are good. I removed the relay, and with a test light (ignition off) tested for ground on #86 and #87. Turned ignition switch on and tested #30 and #85 for power. All checked out. Jumpered the fan to the pos. battery post and the fan works fine. Jumpered the temperature switch wire to ground and the fan works fine. Replaced the wire from #30 on the relay to the battery with a #10awg wire and a new fusable link. I don't have a clue as to what to do now as you's can tell. Help...again....I really don't want to go back to the flex fan. Maybe the alternator isnt putting out enough or gremlins.

[Longhorn Man]

is your temp switch designed to have 12 volts to it, or is it suppoesedto be running the negitive side of the power?
One thing I would recomend, move that switch to the rad. your fan doesn't cool the engine, so it doesn't matter what the temp is of the engine. The fan cools the water in the rad, so it is the temp of the rad that matters. The coolant then goes and cools the engine.
If you think of how the cooling system works, the engine gets warm, the t-stat opens, then the coolant goes to the rad to cool off. When this happens, the cooler coolant in the rad goes into the engione and cools it off.
Having the engine temp control the fan makes no sence at all. You need the sensor to be in the rad.

[Painter D]

do you have to have the temp sensor for the fan ,or do you just want it hooked up that way? i only ask , because i have a corvette elec. fan that i hooked up with a relay that runs all the time( when the key is on) ,and it works great. im decent with electric problems, usually when theres less involved the easier things seem to go. hope i helped, a little atleast.

[DavesRide]

Is that an on/off switch on the head or a potentiometer type for a gauge. Yes I would rely on the one in the radiator first for fan operation. The one on the head may be for gauge and or incorrect for fan on and off.....

[Longhorn Man]

running a fan all the time like 69chevyshort describes is not a good idea either.
it puts a huge load on teh alt and even on the battery, drasticly shortening the life of both items
The fan it's self will have a shortened life.
Having it on all the time will make it run probably about 8 or 9 times more than it normally would. When you are on the freeway, the fan should pretty much never come on unless you have A/C on or you are towing/hauling. So ALL those miles you put on at speeds over 55 or so, the fan is not needed... even in Texas.

[Painter D]

sorry i guess i suggested a bad idea. ive done it that way for years without incident. i try not to post on this site too often for this reason , i seem to always be contradicted. funny thing though im an auotomotive technician, at a FORD dealership here in dfw, but what do i know.

[Longhorn Man]

if it's worked for you, then keep on keepin on.
How many fords are wired that way?
I work in a diesle/fleet shop myself, and spend 7 years turning wrenches on heavy equipment in the army. At our shop we work on everything from escorts to pertbuilts, and for a few years we were rebuilding frito lay P/30 step vans, and one of the upgrades they got was an electric fan if the truck got the 4BTA cummins engine. At first Frito had us wire them up to the engine... they didn't work properly, and they lost some engines. Running a fan all the time isn't a good idea for the reasons I listed above.
So look at how the OEMs do it... sensors in the rad. Makes sence.

[Painter D]

sorry if i offended you dude , it just seems that i always do get contradicicted when i post here. next time your in dfw ill buy you a beer.

[Longhorn Man]

I'm not offended man, I was actually afraid I offended YOU.
I get contradicted quite a bit, we all have our own way of doing things, and I don't always agree with the OEMs, nor the normal beaten path. Many people on here have made mods that I find to be in poor judgement and short sighted... not to mention, not within compliance with federal DOT regulations. But, it was like beating a dead horse, so I stopped.

[Painter D]

no sweat dude. oh yeah i only wire my own stuff up like that. it probably works better with the sensor anyway, but i didnt do my 69 that way.

[Husker]

I use a Relay powered from the old coil wire, I have HEI.
Works great you come off the batt for power.
Ron