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Original 1970 LS-5. Blower will not work.I installed new relay on firewall. Asked for a/c type. Can I tell externally if correct one? Hooks to wiring harness correctly. With engine off, ignition on, blower doesn't work. I have a full 12 volts at orange terminal coming in. No voltage coming out at other terminals. With blower switch in high, I still have no voltage at blue terminal. I have checked ground at relay and is good. Blower is also new item and will work when wired directly. Blower has never worked since bought car. What is my next step? I have not tried with car running. Should this be done? What's up?
 

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If no one shows up, I'll check schematics in the morning. Sounds like no power to the relay coil. Think I have one for a 69 at work.
 

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You should have 2 orange wires coming into that relay. The large orange wire is 12 volt power to the fan only in high speed. In fact the relay is only used in high speed. The blower fan should run in all lower speeds even with a dead relay.
You should have a smaller orane wire coming into the relay. That's the line that engages the coil. Put the dash selector switch to A/C and turn the speed switch to HI. You should have 12 volts on the smaller orange wire and the relay should "click".
 

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Discussion Starter #4
John, found my wiring schematic for "Astro-Vent & Air Cond." There is no two orange wires in 1970. I have figured out that relay sent is correct and large (single) orange wire incoming to relay is fused. Fuse is good and power coming in to relay good. No power coming out of relay anywhere to blower motor. There is a large purple wire coming out of relay that is spliced by factory. One splice goes to blower and other splice goes to A/C resistor. This is the positive supply to blower. There is no voltage getting to blower on power out side of blower relay. Power in supply is good. Tried jumping past relay with direct wire to blower direct. Blower works fine. Relay is new. Could it be bad? Im burning car! Darn electic gremlins!
 

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The relay needs to have a black wire that is ground for the coil. If it has ground (black wire) and power applied to the blue wire when the blower switch is in high the blower should run at max speed. If the blower doesn't work in any speed check the A/C fuse in the fuse block. It powers the blower in low, med1 and med2 speeds and powers the relay coil in high speed.
 
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