68coupe

Hello Everyone,

I need a little help with my electric fan setup.

Current situation:
I have an electric fan with a temperature sending unit and everything works great. The fan is working properly. It comes on at the right temperature and shuts off at the right temperature. The fan is wired to a relay, so that if the car is off, the fan is off. It is a pretty simple setup.

Here is the problem:
The relay that controls the fan when the car is off and on (not the temperature relay) is wired to the “ign” of the fuse box. This means that when I go to start the car, I click the key over, and the fan starts. The problem is that the fan is sucking power that I need to start the car; making it hard to start. The wire that goes from the ign to the relay is not the power source, it is the trigger that closes the switch, relay, to give the fan power, so a high power source is not necessary.

Question:
Is there a power source that I can run that trigger wire to that will only be on while the car is running and not during ignition startup? In other words, is there a power source that is only on when the car is completely turned over and running and does not have power during ACC, IGN, or while the car is off?

Other information
Ignintion setup: MSD 6AL and distributor
Fan: Perma Cool 16 inch
Fan relay kit: Perma Cool


All suggestions are welcome!
Thanks in advance for your help!
Joe

P.S. If anyone needs any clarification, just let me know. I am not very articulate!

1970-Bronze

I'm not exactly sure I understand.

If the "Ignition" power source only turns on the Relay, it should only be consuming >1 amp so it shouldn't effect your starting ability.

The only time it should even possibly pull enough power to give you a problem is when the engine is still hot and you turn on the car which activates the "Fan" because of the Temperature sending unit.


Now if the latter is the problem, you have a couple of options. Put in an additional switch so you can totally disable the fans when starting. Add a "Time-Delay" circuit so it delays the fans for 20-30 seconds.

oregonsharkman

The easiest solution is to install a manual switch between the relay and the power source....I did this with my dual spal 11" fans so i could run a single fan if i needed to.........You might be a able to find a delay device that turns on say 10 sec or 30 sec after ignition is on, but You might have to go to an electronics store to find one. good luck.

68coupe

Thanks for the reply!
To clarify things, the second situation you mentioned is exactly my problem.
This problem only occurs when the engine is hot and the fan turns on because of the temp sensor.

If possible, I would not like to install an ADDITIONAL circuit. Is it possible to replace the existing relay with a time delay relay? Does that even exist? The wiring in my car is already pretty complicated and messy adding more components will just make it worse.

Have you ever heard of a time delayed relay?

Thanks,
Joe

68coupe

This idea crossed my mind, but the reason I spent all of the money on the temp sensing wiring kit and the relay setup was to avoid a switch all together.

Does that relay exist? A delay relay?
How does it work? Does it only delay at first power up?
If so, that would be perfect!

Thanks for the suggestion!
Joe

FB#1

Yes, they do make them. The ones that i have seen have a small **** that lets you adjust the delay. The only problem I see is that they are wired to a plug-in socket and would be very unsightly in a car.

You can stop by a Radio Shack and see what they look like.

68coupe

It does not look like a regular relay?
Thanks,
Joe

FB#1

I don't know what you call a regular relay. It's a cube thats about 1 1/2" square and about 2" tall, either clear or opaque in color. The socket is usually a brown phenolic piece about 1 1/2" square. It has a small wire bail to hold the relay in place.

GATOR454

Add a relay between your ignition source and your fan relay that is wired to the starter circuit. Starter active no power to the fan relay, starter inactive power to fan relay. I can make a diagram if you need one.

427V8

There is a circuit that is only live when the ignition is in the run position, think of the stereo it shuts off...

Just look around at the fuse box, there is what you are looking for there somewhere...

greg454

Here is what you need. You can set the delay to whatever you want. Expensive at $94.11. Part number 56F1000.

http://www.newark.com/product-detail...D121/4047.html

You can order it from
www.newark.com

68coupe

Is there a picture on the web I could glance at.
Here is a picture of one that LOOKS like the one I have in there.



Is it like that?

Thanks,
Joe

68coupe

The Stereo shuts off when the ignition is in the run position?
I will have to look at that.

What about the wipers? Are those a possibility?
Thanks,
Joe

68coupe

That does look like something I need, but it is a little expensive and big. I wonder if they make a relay that looks just like the one I have, but is delayed 30 secs. Maybe I can get it locally, too!

I do not understand all of those spades though. I only need 4. Two sides of the switch, the ground, and the trigger.
I wonder what all that other stuff is for?

Thanks,
Joe

greg454

pins 1 & 4 are the coil, one side goes to your power supply that turns on with the key, the other to ground. Then use pins 6 & 7 to switch the coil on your other relay. The other terminals are a second set of contacts that you dont need, unless you want to use them to switch something else.

Greg.

68coupe

I think I might be overcomplicating this.
Is there any know circuits that I can tap into?
wipers?
starter?
Anything like that?
I think that would be easier than adding a time delay circuit or another relay. (easier for me that is!)

Know of any wires that are live only when the ignition is in the run position?

Thanks,
Joe

vetteboy1976kr

I don't think that the fans should be kicking on when you are trying to start the car anyway. If everything is wired correctly, the relay should only close the switch contacts when the temp has reached the setpoint (180, 190, etc.). I have one relay with one temp switch on the negative side of the coil. When the car is running the coil is "off" until the temp is reached (about 195) and the switch grounds the neg side of the coil to close the contact. The poitive side of the coil is spliced into one of the terminals on the alternator that only has 12v when the key is on. I have a diagram that may help, PM me if you want it emailed to you. I don't see any reason for a time delay relay, my whole set-up cost me $13 including the temp switch.

EDIT: Sorry, just re-read the previous responses and saw that the fan should be kicking on when the temp is high enough to ground the sensor. You could try setting the temp selector a little higher, but the manaul switch would be the cheapest fix. You probably won't use it that often.

GATOR454

Good thinking 427V8. It's the Accessory circuit. It would not be live during starting. In my 74 it's a brown 12 gauge that runs from the ignition switch to the fuse block. Or you could pick it up after the fuse block, again in my '74 it would be a tan 16 gauge that runs from the acc fuse in the fuse block. You could also pick it up at the radio mine would be the yellow 20 gauge at the radio. You could also pick it up at the wiper, which would be a yellow 18 gauge (you would have power here except at starting since its the ground side that starts the wiper motor).

68coupe

Can I pick up the wiper circuit at the wiper motor under the hood?
If so, which wire would it be?
Thanks,
Joe

GATOR454

Yes. According to my Haynes, wiper power is the same color for all years, so it should be the yellow wire at the wiper motor.

BTW thanks for the thread. I still need to wire my fan. I would have gone for an ignition circuit, now I will head to the wiper motor.