hvac wiring question

by riddick75 Wed Mar 25, 2020 10:09 pm

ok I got a few questions, first one is, orange wire from the vacuum selector, where does it go, it is an a/c car, switch that I bought new has 4 spades, cant find the original yet, and cant remember how many it had, saw on here that the original might have had 5. looking to figure out if it tapped off another spade, what it does exactly, could it be left off and still function minus one feature, like when the selector is turned to defrost it turns the fan on high or something, or if anyone has a wiring diagram with the blower switch that has the orange wire. second is how is the blower motor grounded.

by 73ss Thu Mar 26, 2020 12:16 pm

Orange wire is low speed bypass. When AC is set to Max, Fan runs on hi regardless of fan speed setting.

by Mcarlo77 Thu Mar 26, 2020 1:06 pm

Yes...original switch has 5 connector spades. The orange wire connects to the bottom spade as you show in the photo.

Blower motor has a black ground wire that attaches to a sheet metal screw at the firewall just above it.

by riddick75 Thu Mar 26, 2020 2:22 pm

73ss wrote:Orange wire is low speed bypass. When AC is set to Max, Fan runs on hi regardless of fan speed setting.

ok that makes sense, so im guessing that spade is jumpered off of the high position spade. and if the orange wire is left off it wouldn't be the end of the world.

by riddick75 Thu Mar 26, 2020 2:27 pm

Mcarlo77 wrote:Yes...original switch has 5 connector spades. The orange wire connects to the bottom spade as you show in the photo.

Blower motor has a black ground wire that attaches to a sheet metal screw at the firewall just above it.

do you know if the bottom spade is electrically connected to the high speed blade. and that was what I was thinking for the ground wire on the blower motor its self, I just need to get a screw to secure it tight enough, and you also helped me figure out where that capacitor goes, I had that off to the side because I couldn't remember where it went, thank you.

by Mcarlo77 Thu Mar 26, 2020 8:18 pm

Without digging into it, I couldn't say for sure regarding the high speed spade. Been too long since I studied the wiring schematics. Maybe someone else knows off the top of their head.

by thatfnthing Fri Mar 27, 2020 10:03 am

Yes, the orange wire has juice coming from the selector when the selector is set to A/C max. It in turn connects to the pink wire (I'm assuming you have the original wires and connectors), which is the actual fan switch HI setting, and then trips the relay at the blower box to feed full juice from the orange wire there to the fan motor.

It only happens in the A/C max setting (i.e. not for defrost), so the answer to your original Q is 'yes' you could get rid of the orange wire in the first photo with no ill effects if you don't care about that feature.

by riddick75 Fri Mar 27, 2020 2:37 pm

thatfnthing wrote:Yes, the orange wire has juice coming from the selector when the selector is set to A/C max. It in turn connects to the pink wire (I'm assuming you have the original wires and connectors), which is the actual fan switch HI setting, and then trips the relay at the blower box to feed full juice from the orange wire there to the fan motor.

It only happens in the A/C max setting (i.e. not for defrost), so the answer to your original Q is 'yes' you could get rid of the orange wire in the first photo with no ill effects if you don't care about that feature.

ok thats good to hear, every car i have had I never really used the max a/c. lol. and maybe down the road I could piggy tap the orange to the pink some how, but mostly I was wanting to get the instrument cluster fascia on but this was my hold up and didn't want to put it back together if I would have to take it apart again to fix the one thing. Thank you

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