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Premium Member
1,581 Posts
Discussion Starter · #1 ·
Hey Guys I'm trying to sort through the wiring for my heat\AC circuit. It presently is nonfunctional but hoping to take care of that soon. Here what I know..

The blower motor works...12vts to B+

I found a blower motor relay in the wiring diagram and think I found a relay that will work (mine was missing.)

The relay is not operating because I am not
getting 12volts to the coil of the relay.
I found a 3 pin connector and a single pin connector near the ac case under the hood which appear to be the correct wires according my diagram.
The single wire is Orange(Not the fused one from the Horn relay) and I assume this to be the feed wire for the coil. I assume this should be powered up from the control head..Is this correct?
The heater fuse is okay.

When I apply 12volts to the single pin on the relay coil then the blower motor works.
I guess my electrical question is does the
single pin orange wire go to the ac\heat control head and if so how to electrically check the control head. My diagram is too faded out to read in this area.

The next question is how to remove the heater core..I'm leary of using it without replacing the core. (New interior).

Thanks for your input..

After further checking I found that the orange wire DOES power up but only on low blower speed..Does this point to a bad fan switch?

68 chevelle

[This message has been edited by Importtech (edited 01-11-2003).]

7,762 Posts
Make sure you have the correct orange wire. The single orange wire, in the engine harness isn't used for anything. It's the non A/C blower wire. Chevy just left it in there. Tape it off and tie it back.
The relay is only used in the high speed. Power for the lower speeds comes through the blower resistors. Any voltage on the resistors in the lower speeds?

[This message has been edited by John_Muha (edited 01-11-2003).]
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