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Topic: 1985 blower only runs on high speed

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Re: 1985 blower only runs on high speed (2/12)
 11/25/20 5:36am
Atchafalaya
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Atchafalaya Basin, LA - USA

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Fan switch.

Re: 1985 blower only runs on high speed (3/12)
 11/25/20 8:16am
Geo Ceefour
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Thanks I planned on that next but thought resistor harness might be next step, although car was never exposed to heavy weathering. I will order a switch.

Re: 1985 blower only runs on high speed (4/12)
 11/25/20 9:16am
Atchafalaya
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Geo Ceefour said:

Thanks I planned on that next but thought resistor harness might be next step, although car was never exposed to heavy weathering. I will order a switch.



I was just guessing since you stated you replaced the resistor...not much more to fan speed than that as far as I know.

 

GL

Re: 1985 blower only runs on high speed (5/12)
 11/25/20 9:37pm
Adams' Apple
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1st most obvious thing would be to check the fuses. High speed fan runs off of a relay, the lower speeds off of a fuse.



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Re: 1985 blower only runs on high speed (6/12)
 11/26/20 6:40pm
Geo Ceefour
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Not seeing any blown fuses in panel, unless it’s elsewhere, and not seeing any fuse for blower fan.

Re: 1985 blower only runs on high speed (7/12)
 11/27/20 8:46am
Atchafalaya
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Geo Ceefour said:

Not seeing any blown fuses in panel, unless it’s elsewhere, and not seeing any fuse for blower fan.

 


Two fuses for climate control:

Re: 1985 blower only runs on high speed (8/12)
 11/27/20 9:57pm
Adams' Apple
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I can look in the service manual, but I'm pretty sure the blower relay and resistors get power from a fuse link coming from the starter. I can look tomorrow.



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Re: 1985 blower only runs on high speed (9/12)
 11/28/20 12:06am
Geo Ceefour
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Thanks 

Re: 1985 blower only runs on high speed (10/12)
 11/29/20 10:49am
Adams' Apple
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There is a fuse-link, but it powers the hi speed thru relay only. Check for battery voltage(key ON, fan speed on any speed) on the YELLOW wire at the resistor block. No power there hints at a blower switch issue. ALL fan speeds run thru the blower relay. Disconnect the relay and check for battery voltage on the Red, Dk Blue, and Orange wires(key on, blower on High, A/C set to Vent) The Red wire is from the fuse link, the Orange wire is the high speed fan control from the blower switch, and the Dk Blue wire is for the low/med speed control from the fan switch thru the resistor block. Since you said your high speed works, I'll assume the fuse link is good, and the control signal from the blower switch for High is working. That leaves the Dk. Blue wire. No power there means a problem with the switch, the resistor block(which you replaced) OR in the Dk. Blue wire circuit. IF there IS power on the Dk. Blue wire with this test, then it's time to replace the relay itself.

hth



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Re: 1985 blower only runs on high speed (11/12)
 11/29/20 11:24am
Geo Ceefour
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Thank you very much for your help. Where is the blower relay located? 

Re: 1985 blower only runs on high speed (12/12)
 11/29/20 12:30pm
Adams' Apple
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Mounted right on the blower motor.



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