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Discussion Starter #1
Hey guys. I have a 1984 Chevy C-10 and I had swapped the old 305 which was worn out for a better shaped 305. My A/C never had a belt on it but the controls for it worked and it would push air on the A/C or heater selection, but now my control just isn't working. I replaced the fuse in it. It said "AUX HTR A/C" with an arrow pointing to the lower left of it which had a "25" so I'm guessing that was the right fuse. The fuse is brand new but still the control is not working. It wont even push air or anything. Is there any wiring in the cab from that control that I might have ripped when swapping the engine? Or anything that I could have not plugged back in in the cab? What color are the wires? Anything will help. I really appreciate it. Thanks.
 

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Aux would be for a rear unit , like in a van,fusebox is the same I guess.
You need to look for the heat or AC fuse.
Did you hook up both fusible links at the starter when you swapped engines? Is there anything else that doesnt work on the truck?
A fusible link could also be burnt. Check ALL the fuses with a test light, with the key on. The good ones will have power on both sides of the fuse. A blown fuse wont. If some of the fuses never have power no matter what, that would indicate an open circuit, like a blown fuse link.
Also fuses for lights and such wont have power without the light switch being on.Check it out, post back.
 

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Well for a while there my truck battery kept dying because of a short when I let it sit over night but my dad unplugged something and it went away. It was an orange wire that had like a fuse in a white plastic cover with a screw on top that went into a brass looking hookup that was mounted on top of the drivers side tire well. I'll put up some pictures of it and the fuse box.
 

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That was probably the power feed for the heater ac from the sounds of it.
Something on that circuit was staying on.
 

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That is for an auxiliary AC Heat , like in a van. The fuse box is used in G K and C chassis, maybe more.
It wont be used as a pickup doesnt have a need for a rear AC.
Check all the fuses , be sure they are good.
The inline fuse holder looks like something added by a previous owner.
Did you check the fuses? you could check for power at the rear of the heater control.The function part (AC Heat def etc) has a switch that powers the fan switch circuit. If it doesnt power the fan switch, the fan wont run, and most likely neither will the AC compressor.
Check for power there next. IIRC the power wire will be orange or tan.
 

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Discussion Starter #7
I will check the power on everything tomorrow and see where that orange wire runs for sure and if I need it or not. I'll let you know.
 

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On these trucks there is a separate 30 amp fuse under the hood for powering the high speed blower relay. It is usually in an orange line that runs across the back of the engine compartment from a junction on the driver's side to the blower motor on the passenger side. This is only used when the blower is on high, so the lower speeds should work if it is blown. On my '75 truck the old round fuse kept overheating and melting the holder, so I spliced in a new fuse holder with a blade fuse. Yours should already have blade fuses, unless they kept the old style.

Lower blower motor speeds (all but max) run through the fuse panel and the resistor pack that is mounted on the A/C plenum under the hood. The high speed blower relay is also mounted there. The resistor pack may have failed, and it usually takes out the lowest speed first since it is used most frequently

According to the diagram here " Chevy Truck Fuse Block Diagrams - Chuck's Chevy Truck Pages " for an '80 truck (lower on the page), you are replacing the wrong fuse. You need to replace the B fuse for the heat/air, not the E fuse that you found.

Bruce
 

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If that's for the high blower, wheres the fuse for the lower speeds? In the fuse block?
Yes, the 2 or 3 low speeds are fed from the under DASH fuse block. When switched to high speed, the power flows to the HI relay COIL to energize the relay, which in turn supplys the blower with Full battery voltage VIA the orange wire and bigger fuse.
 
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