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Blower Wiring (Had AC But Now It Does Not)

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I have a 1980 Firebird Esprit.

It had AC at one time, and Now it does not.

All I have is a fan switch (all other levers for ac and heat have been removed).

Under the hood are the blower (fan), blower resistor, and blower relay. I have no wires to any of these three devices.

After much research, I drew the attached diagram.

I tested the resistor with an ohmmeter, and it seems to be working.

The relay reads nothing on the ohmmeter, and I will replace that.

Blower Switch:
4 terminals
3 position lever (Low, Medium Low, and Medium-High).

Blower Resistor:
4 terminals (low, medium-low, medium-high, and power out to relay)

Blower Relay:
5 terminals (**I do not know which terminal does what or what color wire below connects to which terminal)

I do know that:
The red wire is for power from the alternator
The black wire is ground
Orange wire is switched power (I'm assuming it goes back to the blower switch)
Dark Blue wire carries varying volts from the resistor)
Purple wire power to Blower


So my questions are:
1) How do I wire up the relay (which terminal connects to which wire)

2) I understand the blower is ALWAYS running on low.

The blower switch inside car has only three positions (L, ML, and MH). Somehow, the relay makes Blower run on High.

Shouldn't there be a switch or something to make it run on High?

IMG_3346.jpg
 
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Can I skip the Blower Relay altogether?

If I did, I would have the Dark Blue wire from the resistor running to the Blower?

This should give me Low, Medium Low, and Medium-High.

I would not have a High.

I don't understand what controls the Blower Relay, so it knows when to "cut out" and run on high.

(I do not have any other levers on the ac/heater control inside the cab.
 
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So I need to figure out what wires go to #1, #2, #3, #4, and #5 in the attached pdf.
 

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  • Blower Wire Diagram 2.pdf
    104.6 KB · Views: 4
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Did a bench test last night with the old blower.

Worked fine on all speeds (L, ML, MH, and H)

Skipped the relay altogether.

Redrew the wiring diagram.

See below.

Now to wire up the new blower.
 

Attachments

  • Blower Wire Diagram 2 (1).pdf
    165.7 KB · Views: 9