1950 Mercury Heater Q's

[Sixseven]

Seeking clarification on the heater operation for this car. The heater switch, fan, plenum and heater core all appear factory installed. My heater motor does not operate.

The switch seems to have one stop when pulled out suggesting single speed heater fan, true?

The heater motor has three wires, one of which is ground. What type of motor is this?

How does the knob come off the shaft, or if the knob and shaft are permanently connected, how does the shaft come out?

I've search this forum for heater wiring diagrams but find nothing for this car. What does the heater wiring diagram look like. I've also searched the Van Pelt site and find nothing for the heater.

[Dan in MI]

I'll try to help with some info from my 49 Ford wagon, hopefully the Merc is the same. The 49 and 50 used a single speed motor (2 wire) with a resistor in the blower switch to attain 2 speed operation. The switch was off when all the way in, high in the middle and low all the way out. In 51 they went to a true 2 speed motor with 3 wires (orange - high, red - low and ground) with the red and orange coming from the control.

Can you feel / see the resistor on the back of the switch? How about wires?

Maybe at sometime the blower motor was replaced and the replacement motor was a 3 wire and you just used the high and ground wires for a 49 - 50?

[Dan in MI]

I found the wiring diagram for the Ford in the shop manual section 11 - Accessories. Do you have a Merc shop manual?

Ford manual pictures attached.

[Sixseven]

Dan, thanks. I'm going to go investigate now. I have only one position on my switch. I'll double check that too.

[Sixseven]

Definately a single step switch, must be different than the Ford. The owners manual also shows the switch as a one step switch. The back of the dash is tight and full view of the blower switch is blocked by the ignition. Pressing onward as cool weather is starting to set in.

Thanks for responding Dan!

[Sixseven]

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Originally Posted by Dan in MI

I found the wiring diagram for the Ford in the shop manual section 11 - Accessories. Do you have a Merc shop manual?

Ford manual pictures attached.

Yes, I have a reprint manual but it isn't showing me the detail that you have.

[Dan in MI]

The operating instructions for the heater are in the instruction pamphlet in the glove box. Maybe your single step switch turns once you pull it out for high and low speed.

[rotorwrench]

Both of my 51 Mercury cars have a 2-speed switch and a 3-wire motor. Later cars started using a single speed motor but had dropping resistors mounted in the plenum to keep the resistors cool and out of reach. The resistors would lower the motor speed depending on switch position.

[Sixseven]

Investigation and repairs completed. The switch had faulty contacts on spring loaded shaft. It is a two speed switch now that I've removed the gummy grease. I soldered a bubble of solder on top of the two contact points. and heated them enough to create a smooth bubble for the contact point. I'm not sure if this repair will past as the solder may be softer than the original material. Once I cleaned the switch and repaired the contacts, the heater now works. I might pull the motor and clean it up plus check the bushings in it.

Thanls for y'alls help!