1972 Plymouth RR --> HEATER NOT WORKING

[zextrot]

What is the most common issue - bad switch control? Where can i purchase replacement parts?

[JimT1971RR]

I would start my taking a multi meter and checking various points for voltage. At the harness, at the switch, etc. See where the problem is before you start looking for replacement parts.

[zextrot]

I could use a diagram identifying all the heater parts and their location. Would you happen to have something like that?

[rradar71]

You didn't say what was not working (fan motor,or not heating). I'm not a mechanic, but on my 71 the heater valve is controlled by vacuum. I would check to make sure that the little hose is not cracked. With car warmed up and heater on, both hoses should be hot coming from valve.

[zextrot]

I'm no mechanic either, but my guess is the switch control. I say that because when i turn the heater "on" nothing happens at all.

[rradar71]

If you havn't checked already, I would start with the fuse. On my car its the fuse on the right, second from bottom on fusebox. I have a/c car and its marked heat/ac on the box. Then yeah, the switch. I have a little problem with my fan control, in that sometimes it dosen't stop in the correct place (little bit sloppy). I would still check the operation of the heater valve going into firewall.

[rradar71]

I tried picture but its not working

[zextrot]

i did look at the fuse box, and didnt see any fuses blown. i guess it couldn't hurt to replace the fuse with a new one anyway just to see. is yours vacuum driven??

[zextrot]

please email photo to andrew at thepurplepress dot com

[JimT1971RR]

Sent you a scan out of my 71 book of wire schematic.

Hope it helps.
Jim

[72RoadRunnerGTX]

If you have a non-A/C car without the Strato-Vent option, the heater box is cable controlled, no vacuum actuated functions. Here is the wiring diagram from the FSM for the non A/C blower circuit. see FBBO thread, linked below. Power feed (C1 14BK*, black 14ga wire with a trace) originates at the fuse panel. Should have a fuse labeled “heat-A/C”; check that first then move on the blower switch, from there to the resister pack. Some common issues are overheated connections however with no blower function at all I’d be looking for issues common to all speeds, complete disconnections at the blower switch, resistor pack, disconnected blower motor ground, bad blower motor, need I mention blown fuse.

Check your FBBO thread on this, I posted some full sized pictures there I can't here.

[zextrot]

You are the man!! THANK YOU!

One more thing - where do you connect vac lines for your charcoal/vapor canister?

[72RoadRunnerGTX]

On the 4-port one year only ’72 canister, all ports are clearly labeled. A line connects to the fuel tank vapor separator via a hardline at the inner fender, a line to the enclosed carb bowl vent on OE carbs, a purge line connects to a tee in the PCV hose, and the fourth is connected to a tee in the vacuum advance hose. Be sure to check the diaphragm on the purge control valve; tend to develop pin holes over all this time. The diaphragm cover with the small port un-snaps or just vacuum test it at the port with a hand pump.

[zextrot]

Awesome! Now that you've given me all this knowledge, I am trying to put it to use. The instrument panel bezel is not wanting to come off. Seems like something behind the steering column is still holding it on. Any ideas? I need to get access to the gauges and heater control, air grabber control, etc.

[72RoadRunnerGTX]

Pulling the cluster? Did you get the two screws, one on each side of the column accessed from underneath?