[mlund888]

Hello guys,
Got my 63 on the road this weekend at Adirondack Nationals, tan great but I discovered if driving with parking or headlights on my fan would work, with it off, no electric fan?
Everything is new, have 2 -12 inch fans with relays and rechecked my grounds? I am running a toggle switch in place of temperature switch
Also, if running both at night voltage gauge drops from just under 14 to just under 12, if I cut fans off, voltage jumps back up
I’m conpletely lost on this, stock fuse panel and switches and I never even touched the headlight switch?
Thank you

[mlund888]

I forgot to add, same thing happens whether or not, the car is running.

[Scott65]

What is the output of your alternator? Possibly, it's marginal for the amount you need.

[mlund888]

100 amp, no ac, or radio

[Scott65]

Maybe you have a generator on a 63? I'm no help with that, hopefully those well versed will be along soon if so.

[Scott65]

Where are the relays for the fan powered from? Also, where is the wire for the relay coil powered from. The fans only working with the lights on means your power supply is off of something that only has power when the lights are on. Easily enough checked with a voltmeter. For the low voltage situation, look on Mad Enterprises Web site for an article that discusses voltage sensing and various ways to wire the alternator so that it better senses voltage requirements. That should help as long as your alternator is truly capable of putting out the 100 amps advertised.

[mlund888]

Hello Scott
Thanks for helping me out.... I’ll double check tomorrow as to the 12V power source to my relays.... I’m fairly certain they are from battery lug I have near the firewall, but what you said makes sense

[Scott65]

And the main power, or the wire going to terminal 30, may very well be. If so, check 85, or 86 whichever you're using to power the coil. Make sure it's from a source that's got power with the key on, and it'll run any time the key is on.

[mlund888]

I have constant power
One to fan motor
One to ground
And the other is to my toggle switch, which is grounded

If I ran a 12V source from the Battery bypassing the source from the lug and it still acts the same way.... any other thoughts?

[Lee]

Originally Posted by Scott65

Where are the relays for the fan powered from? Also, where is the wire for the relay coil powered from. The fans only working with the lights on means your power supply is off of something that only has power when the lights are on. Easily enough checked with a voltmeter. For the low voltage situation, look on Mad Enterprises Web site for an article that discusses voltage sensing and various ways to wire the alternator so that it better senses voltage requirements. That should help as long as your alternator is truly capable of putting out the 100 amps advertised.

Ditto on the MAD Enterprises website. There are some very informative booklets for sale on that site, if you want to have an even better understanding of the electrical systems.

Is your alternator a 1-wire version?

[mlund888]

Yes it is a one wire
I have the same set up on my 40 Ford Coupe and have never had a problem

[Lee]

I suspect that either the alternator is not producing the amperage that it is advertised at, or you have excessive resistance somewhere in the circuit. Resistance may show itself by making a wire or connection very hot (check carefully to avoid getting burned).

Here is a link with a chart showing wire gauges for different amperages (example: for a 4' wire to carry 100amps to your distribution lug, it suggests an a 8-ga wire) http://www.offroaders.com/technical/...gauge-to-amps/

[Bill Hanlon]

Originally Posted by mlund888

Yes it is a one wire
I have the same set up on my 40 Ford Coupe and have never had a problem

Does your '40 have dual electric fans? Is the electrical source for the fans near the alternator output?

One wire alternators are notorious for not sensing load properly.

[Scott65]

Originally Posted by mlund888

I have constant power
One to fan motor
One to ground
And the other is to my toggle switch, which is grounded

If I ran a 12V source from the Battery bypassing the source from the lug and it still acts the same way.... any other thoughts?

Which relay terminal goes to the toggle switch?

[mlund888]

My 40 is a single fan with relay and also with toggle switch
For my 63, I’d have to look tomorrow to see which one is going the toggle switch

[Scott65]

Let us know what each relay terminal is wired to, and I'll bet you'll get an answer to solve your problem. But basically, if it's a Bosch style relay, 30 should go to Bat 12v, 87 to your load (fan) 85 to grnd, and 86 to switched 12v.(something that is powered under the conditions which you desire the accessory (fan) to operate, key on probably in your circumstance. They can be made to operate by switching the coil grnd also. And Ive heard that 85 and 86, either can be switched 12v, and either can be grnd. But I stick to the way I mentioned first just to keep from confusing myself, and I know it works... I'm not an electrician, so I try to keep it simple...