How do I reverse it from PUSH to PULL

[white99c2]

I installed the rear condenser fan and relay as shown in the drawing and it and it worked, turn on the AC and the fan comes on. The air from the fan is blowing out of the engine bay grill instead of sucking air in..

The instructions for the fan say to change it to a puller reverse the fan blade and reverse the blue and black wires. I reversed the fan blade and put the blue to terminal 87 and the black to ground and the fuse blew. What should I do?

[DRACO A5OG]

reverse polarity or flip the fan motor

Which brand of fan did you get?

When I installed my fron oil cooler fan, My fan was binding and causing the fuse to blow.

[911pcars]

Your text description could be interpreted differently.

By reversing polarity, current flow through the motor is in the opposite direction. Thus if terminal 87 of the relay is providing source voltage to the fan via the black fan wire and the blue fan wire is connected to ground, reversing current flow direction requires:

a. terminal 87 connects to the blue fan wire.
and
b. the black fan wire connects to ground.

With the this setup, the fan motor should rotate in the opposite direction. Not sure reversing the fan blade is necessary. It depends on the shape of the fan blades.

Hope this helps,
Sherwood

[white99c2]

911pcars that is exactly what I did and it blows the 25 amp fused like going to terminal 30.

[gsmith660]

You are blowing the fuse because you are putting the fuse straight to ground at the relay dont change anything at the relay, what you need to do is do one of the 2 not both is AT the motor swap the blue and black wires which reverses the polarity of the motor OR reverse the pitch of the fan if you do both then the motor will still blow out just rotate in the opposite direction

[white99c2]

Thanks for posting a reply. I'm thinking about what you wrote and isn't it the same doing it up by the motor or down by the relay next to the engine bay fuse panel.

I looked at the drawing and the way it is wired now the blue wire is going to ground. If I were to switch the polarity at the motor than the blue wire would now be headed towards terminal 87 on the relay and the black would be going to ground. Wouldn't that cause the same result as putting the hot straight to ground and popping the fuse.

My gut tells me that I've got to re-wire the relay to make this work.

[gsmith660]

No the reason you are popping the fuse is because you have the blue going to ground like a short if you want to reverse the polarity of the motor then switch the wires at the motor this reverses the field and makes the motor spin the opposite way, you should not do anything at the relay all the relay is doing is supplying power to the motor and is wired correctly by your diagram above.

[ossiblue]

You may wish to check the grounding of the fan motor itself--meaning, the blue wire may be a secondary ground to an already grounded DC motor. Disconnect the black and blue wires from the motor. With a test light hooked up to power, touch the blue connector on the motor. If the test light goes on, then you know the blue connector is a constant ground and that's why you are blowing the fuse. If that's the case, reversing the blade is the only to change airflow.

If you do not get a light by touching the blue connector, then simply switching the connections at the motor should reverse the spin as mentioned but if you've already switched the fan blade, you will be back in the original airflow pattern. Do one or the other (blade or wiring switch), not both.

edit: gsmith660 posted before I finished typing and he is absolutely correct. I was really confused by your post but now I think I see what happened. If you connected the blue wire to terminal 87 by removing the connector from the motor and attaching it to terminal 87, you are directly grounding terminal 87 because the blue wire is a ground wire. Is that what you did? Follow gsmith660's lead and simply switch the connectors at the motor--it will work. Keep in mind the already switching of the fan blade, however!

[white99c2]

The fan in question is a Hayden, the directions are very specific, they state to change from push to pull change the direction of the fan blade and reverse the wiring.

Ironically I eliminated the relay and connected the blue directly to ground and the black to 25 amp fused and the fan reverses.

The motor is sealed, no way to reverse the wiring at the motor, the only way to do it is to reverse the leads, blue and black.

Is there an alternative way to wire the relay, I think that is the answer. I just don't know how to do it.

[shbop]

http://www.classictruckshop.com/clubs/earlyburbs/projects/bosch/relay.htm

This site may help you understand the rely itself.

[white99c2]

JON that helps and leads me to believe that the above wiring diagram for the relay is for a GROUND TO TURN ON A CIRCUIT, how do I set this up for a POWER TO TURN ON A CIRCUIT using a relay that has terminals 30, 85, 86 and 87;

Can you fill in the blanks?
__________________________________________________ ________________\

POWER TO TURN ON A CIRCUIT

#30 -
#85 -
#86 -
#87 -
Positive lead from fan -
Ground from fan -

[shbop]

I'll take a shot, with the following caveat: I'm not an expert.

#30: is power from your 12 volt source. Usually the battery. I always protect this wire with a fuseable link, at it's source. Keep in mind that we often use relays to provide an alternate path for current.

#85: should be your ground. (-)

#86: this is the source that turns the relay on, and is connected to your switch. In your case, this is probably the a/c compresor wire, if you want the fan on every time the a/c is switched on.

#87: this goes to your fan. (+)

There are many different ways to use a relay. Your devise can be triggered by attention to ground (-), or a (+) source. Hope this helps.

[gsmith660]

Black to fuse
blue to 87
30 to ground
85 and 86 same as they are

[gsmith660]

Or an alternative that stays with the gen. wiring convention for the relay

30 to a/c pwr lead
87 to ground
85 to ground
86 to blue wire

[white99c2]

Black to fuse
blue to 87
30 to ground
85 and 86 same as they are
______________________________________________

30 to a/c pwr lead
87 to ground
85 to ground
86 to blue wire

______________________________________________

In both of these set-ups I am not bringing a fused 25 amp power lead to the relay. The bottom one is using the AC power lead to the relay. Where does the black lead from the fan go?

[gsmith660]

Black lead goes to the fuse you are using the relay to trigger your ground and turn on the fan when your a/c compressor turns on. Relays can do many things I used a relay to reverse the logic of my fuel pump to my EFI computer much the same way I used the efi comp. 12v lead to send a ground signal to the relay.

[911pcars]

Originally Posted by gsmith660

Black lead goes to the fuse you are using the relay to trigger your ground and turn on the fan when your a/c compressor turns on. Relays can do many things I used a relay to reverse the logic of my fuel pump to my EFI computer much the same way I used the efi comp. 12v lead to send a ground signal to the relay.

Your good suggestions would be much clearer to understand by adding some strategically-placed punctuation marks.

Thanks,
Sherwood

[rick-l]

I have no clue what this conversation is about but that relay is a SPDT relay. It has a terminal 87A.

[white99c2]

I switched the blue/black and switched 85 and 86. The fuse did not blow, tried 85 and 86 in the original locations as in the drawing above and bam, the fuse blew.

So there must be some weird diode on the pulse for 85 and 86 in this relay, who knows.

All is good, it turns on and off with the AC and is now sucking into the engine bay, its powerful 880 CFM's.

Thank you to all that contributed.

Rob

[Mysterytrain]

Sorry I was a little late to the party...