1972 Heater Blower Motor Wiring

[beatnavy]

I'm trying to get the heater blower motor working on my 1972 1.7L. I know the motor works, as it will ran when I put a jumper between the pins (30 and 87?) on the relay board. The motor sounded like a dying cat, but I managed to clean it up and put some lubricating oil on it, and it seems to run fine when jumped or hooked up to a 12 V source. I believe this motor is supposed to run when the lever near the gear shift is pulled up high enough to ground the wire attached. Unfortunately, the wiring seems to be jacked up. I think I have at least two problems:

1. I'm not getting any power to the hot wire that connects to the blower motor, best I can tell.

2. There is no wire connected to the heat adjustment lever. I disconnected it from the floor pan, and there is the end of a wire connector connected to it, but the ground wire must have been cut long ago, and I see no sign of it anywhere in that tunnel. The blower motor does seem to be grounded to the engine tin in front of the distributor (not sure if that was something someone did to make it work of if that's normal).

Is the blower motor activated by simply that wire (that I don't have) grounding at the heat adjustment lever? If so, what's the most likely cause of no voltage at the wire going to the heater motor lead?

[bowlsby]

That ground wire is standard for a 1972 914. How about the blower relay, does it work?

[Dave at Pelican Parts]

The lever grounds that wire, which triggers the relay to send power to the fan. The fan itself is permanently grounded via the brown wire that plugs into it. Sounds like you need to replace the wire, or find it again and connect it correctly.

--DD

[beatnavy]

I've done some more troubleshooting, but should I be using the wiring diagram for '71 or '73 (or something else all together)? I'm assuming '71 based on what I see, but not sure. Here's what I've found:

1. I think the relay is good.

2. The Brown Lead at the blower motor is grounded.

3. The Green Lead at the blower motor has continuity to pin connector 11a (the connector on the relay board that's toward the rear of the car).

4. On the connector on the front of the relay board, I don't even SEE an electrical lead in connector hole 11. Is that normal?

5. If I am using the '71 diagram, I guess I need to find a way to get a wire to connector hole 9 from....somewhere...ideally to the heater control lever, correct?