Heater fan operation, troubleshooting Options

[malcolm2]

The only thing installed on my car that is associated with HEAT would be the exchangers. Nothing else. I need to get the heat working so I started with the Heater fan in the engine bay.

SO FAR:
successfully bench tested the fan with 12v.
Put a known good headlight relay in the fan relay socket
Successfully checked continuity of the wire from the lever to the 14-pin connector (GRN/wht). Connector attatched, and unattached
Successfully checked continuity from the relay (87) to the fan (green wire), car was not running.

Strange thing I noticed. Checking continuity from the lever to Pin #9 was good. I then checked continuity between the lever and pin 13, 11, 7, 5, 3, 2 & 1. With the 14-pin connector connected they all showed continuity to ground. THIS CAN"T BE RIGHT, can it? The car runs fine, all the lights work. Seems like a ground short, but it is not affecting anything else.

My goal here was to (as designed) get 12v to the green wire on the fan, but I can't. I have read several posts that gave me some direction. But I am lost.


Thanks,

Clark

[Dave_Darling]

Not sure about the "continuity with everything" bit.

But here is how the heater blower circuit works:

The switch on the bottom of the "DEFROST" lever gets grounded when you pull the lever up high enough. That grounds one of the control pins (85 or 86, forget which) of the heater blower relay, which sends power from #30 of the relay to #87 of the relay. That power is what runs the fan.

Power gets to #30 of the relay through one of the fuses on the relay board.

I don't remember how power gets to the other control pin of the relay, but it should be "switched power".

--DD

[malcolm2]

But here is how the heater blower circuit works:

The switch on the bottom of the "DEFROST" lever gets grounded when you pull the lever up high enough. That grounds one of the control pins (85 or 86, forget which) of the heater blower relay, which sends power from #30 of the relay to #87 of the relay. That power is what runs the fan.

Power gets to #30 of the relay through one of the fuses on the relay board.

I don't remember how power gets to the other control pin of the relay, but it should be "switched power".

--DD

Here is what I figured from the diagrams, etc....

The lever grounds pin 9 in the 12-pin connector,
that goes to (grounds?) 86 in the relay and should change the state of the relay so 87 and 85 in the relay connect.
85 gets power from pin 7 in the 14-pin connector, pin 7 brings 12v from the coil. 87 then sends 12v to pin 11
that is jumped to pin 10 ( both on 12-pin conn).
Pin 10 goes to pin 11 on the 12-pin connector, and that has the green wire to the fan.
The fan is grounded with a brown wire.

I will check all with the meter again. Nice design of the 12 & 14 pin connectors. Just remove the cap and everything can be tested. (IMG:style_emoticons/default/piratenanner.gif)

As a test, could I remove the relay and insert a 12v wire into the socket of 87, 2nd test, jumper 86/87 and put 12v at pin 9?
My crude drawing.... (IMG:style_emoticons/default/lol-2.gif)



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