Supercharged Heater Fan Upgrade

[basketcase0302]

Bump!

Man I wish I had found this when rebuilding my heater!
Oh well, there will always be upgrades I'll want to do on the bump.
Real good stuff KnightFire83!

[austin]

i love the idea but im an idot when it come to wiring and im not sure what your doing it looks like your wiring in a seprate switch for high speed on the blower motor is that it?

[basketcase0302]

it looks like your wiring in a seprate switch for high speed on the blower motor is that it?

Austin, you're kinda' right...
The relay is acting as a switch to send power to the heater motor, (via the high speed power wire from the existing fan switch). You use a fused separate power source for the relay. The 12 volt relays aren't that hard to wire once you've done just one of them, and almost all of them come with wiring diagrams.

[knightfire83]

[austin]

oh cool i get it now thanks guys

[Mancar1]

Great info, and thanks for the pics.

[tsherry]

I took a little different tack on this upgrade, although I have all the parts I need to complete the upgrade to the Jeep motor upgrade.

1) Replaced the fan squirrel cage with the Bump sized cage, including the Dremel work to get it to fit in the plenum.
2) Managed to break the plastic cage in the effort.
3) Remembered that I had two metal squirrel cages from an interior house fan...dug them out, they matched the plastic '72 cage perfectly.
4) Installed the aluminum cage directly on the '67 motor, and installed the assembly in the plenum.
5) Dramatic increase in airflow. No increased temperature in the switch, as the motor didn't change and the resistance from the larger cage didn't seem to affect the power draw.

So for now, in this installation, the '67 motor with a larger cage works for me. I'll try the Jeep motor on the 'other' cage and see how it compares.

[basketcase0302]

tsherry on Wed Nov 21, 2012 10:11 pm
I took a little different tack on this upgrade, although I have all the parts I need to complete the upgrade to the Jeep motor upgrade.

1) Replaced the fan squirrel cage with the Bump sized cage, including the Dremel work to get it to fit in the plenum.
2) Managed to break the plastic cage in the effort.
3) Remembered that I had two metal squirrel cages from an interior house fan...dug them out, they matched the plastic '72 cage perfectly.
4) Installed the aluminum cage directly on the '67 motor, and installed the assembly in the plenum.
5) Dramatic increase in airflow. No increased temperature in the switch, as the motor didn't change and the resistance from the larger cage didn't seem to affect the power draw.

So for now, in this installation, the '67 motor with a larger cage works for me. I'll try the Jeep motor on the 'other' cage and see how it compares.

is a really good idea on the squirrel cage, (coming from an HVAC guy who has installed them for over 30 years).

[austin]

yesterday i bought a power probe then i used it tonight to figure out why my blower motor quit working, it turns out i accidently unplugged it while i was repairing my speaker wires

but i noticed with this fancy new tool that there is only 10v of power going to the motor on the high setting and when i used the jumper setting and applied 11.5 volts to motor it spun slightly quicker so im thinking the for those who dont want to change thier blower motor could simply wire in the relay like shown in this thread and it would deffinatly help

[Alfred Lord Tenniscourt]

Thanks for the great thread guys!
I just threw in a great, big fan and motor from an explorer, and it sounds like a spaceship is about to take off when I turn it on... It's great.
However, I am having problems with the relay staying energized for some reason, and therefore can't get the darn thing to turn off! Anyone manage to run into this one yet?

PS - This is really weird because when the switch is between settings, the fan will shut down. If I then flip the fan over to the off setting, it stays off. It is even weirder because with the switch in the off position, I have continuity between the 12 volt signal, the six volt power line, and ground... Just as one would expect. Also, the relay de-energizes when I flip the switch over to the low setting like it should.

[basketcase0302]

Alfred Lord Tenniscourt on Mon Jan 14, 2013 7:13 pm
Thanks for the great thread guys!
I just threw in a great, big fan and motor from an explorer, and it sounds like a spaceship is about to take off when I turn it on... It's great.
However, I am having problems with the relay staying energized for some reason, and therefore can't get the darn thing to turn off! Anyone manage to run into this one yet?

PS - This is really weird because when the switch is between settings, the fan will shut down. If I then flip the fan over to the off setting, it stays off. It is even weirder because with the switch in the off position, I have continuity between the 12 volt signal, the six volt power line, and ground... Just as one would expect. Also, the relay de-energizes when I flip the switch over to the low setting like it should.

If I understand your question right-are you supplying the coil of the relay with 12 volts? A reduced voltage on the coil side of the relay will allow it to "drop out" intermittently.

[Alfred Lord Tenniscourt]

Yeppers. Reduced voltage on the coil side (I was calling it the "signal" side).
I think I might have it figured out...
Since I have a '67, my switch is a little different. When the switch is in the off position, the terminal that goes to the resistor, and the terminal that goes to the coil on the relay relay are connected for some reason. What I think is happening is that in the off position, the motor is acting as a generator as it coasts to a stop, and since the coil side of the relay is switched to the resistor when the switch is in the off position, it is sending just enough power to hold the relay closed back to the coil side of the relay to switch it on.
I could throw a diode in series with the resistor I guess and see if that stops it.