Fan Not Working

[bordin34]

The fan on my 1973 Charger is not working. When I moved the heat switch from heat to defrost or from setting to setting I can hear the ducts opening and closing. I think either the fan switch does work or the fan motor is broken. Is there an easy way to test this?

[RD]

there should be a relay on the bottom of the blower/heater core housing, i would run a check there to see if that is working properly.

[Nacho-RT74]

there is not a relay on blower system on B bodies and in fact that is what melts the switch and plug frequently.

To check blower is simply, just feed directly form batt the blower on engine bay ( green wire )

[willille]

My switch did not melt but it sure did a number on the fuse and fuse block.

[Nacho-RT74]

My switch did not melt but it sure did a number on the fuse and fuse block.

yeah that too... second from bottom to top, acc side

[Nacho-RT74]

The fan on my 1973 Charger is not working. When I moved the heat switch from heat to defrost or from setting to setting I can hear the ducts opening and closing. I think either the fan switch does work or the fan motor is broken. Is there an easy way to test this?

first check for working motor. feed directly from batt. Then will go to next step



73/74 is diff about the lever fan switch plug, but wires route are the same and same color

Some Notes:
A/C cars are LOW SPEED turn on by default. I mean even if you unplug the lever fan switch, blower will be still working on low speed since TURN ON CONTROL switch sends power directly to resistor, spliced from fan lever plug itself.

SO you can check if TAN wire on resistor plugs is getting power when you turn on the A/C control. This wire is ALLWAYS powered ( is the low speed ). If you don't have power there, then Control switch is damaged or allmost gone. Sometimes they endind having an inner "play".

Heater uses another wire to feed blower... brown wire. That sets up a JUST ONE SPEED to heater function.

Light green on resistor and lever switch is mid speed.

Dark green wire on fan plug is a direct to blower source. Doesn't run to resistor. Same green wire is also spliced on bulkhead because same green wire comes from resistor but just as a resistor low, mid and heater speeds output.

P.S.:
is a 71 diagram, so blower and clucth wires arrived to bulkhead on tranny harness area. since 72 those wires could or not arrive to bulhead and use a grommet on firewall instead, because one more wires were added to electrical system, groun NSS to setabelts function... so depending on equipment options.

Tipically, on non tach cars, blower wire still arrived to same cavity used on 71 and clutch wire then use the only cavity empty on engine harness

[1973rallye]

Old thread but I am now having a similar problem. Blower motor runs with direct power.
At resistor;
On AC, power to single tan for low speed.
On medium, power to single tan and also to light green.
On high, power to single tan and also dark green.

On heat at resistor;
Low speed, power to tan at three prong.
Medium, power to tan again on three prong
High speed, power to tan again. This doesn't seem right as I would expect the light and dark green wires to power at the related med and high fan speeds.

Power all over the place but nothing seems to activate the fan.  Because I get different wires showing power at the resistor it tells me the switch is ok! Or is it?  What's left other than the heater/AC controller. 

Any ideas gang?

[1973rallye]

Fortunate to have a Technician in the family. Popped over after dinner and within 5 mins he had everything working. 
Problem solved.

[Nacho-RT74]

What it was?

[1973rallye]

Almost embarrassed to say Nacho. It was the connector at the blower motor. 

[Nacho-RT74]

Lol