Kerouac

Hello Folks: Was driving along with the AC on and it up and died. Air stopped blowing out the vent. The fan does not operate at all. As I look through the Shop Manual it says there is a "3 AG 30 in-line fuse located in the wiring over the evaporator case." Is the photo below that in-line fuse? And if so, how do I open it to check the fuse? Also, when I checked the fuse box in front of the driver's seat I saw that the heater fuse is blown. Would that affect the fan? Thanks.

Nowhere Man

That looks to be the inline fuse. I know for 67 ac the inline fuse is very close to the horn relay where it gets it power. I guess 66 is different. To open it you simply twist it and pull. There are two prongs that seat and latch it.

leif.anderson93

Keith,
I know you meant to say push, twist and pull...spring loaded

Powershift

That's it. The holder is made in two pieces with a spring inside to keep the fuse secure. Push the two ends together and turn 90 degrees counterclockwise with one of the ends.

Then try and find out why the fuse blew.

Larry

Kerouac

I appreciate the knowledge, gentlemen. I will take a look at it later tonight or tomorrow morning and report back. So I assume the blown heater fuse in the fuse box has no bearing on the issue. I probably never noticed that fuse being blown because we don't use the heat too often out here in LA.

Powershift

That fuse probably is for the low and medium speed. If it is blown also, the blower motor may be a problem. Of course there could be other issues as well.

Replace both fuses and then see what happens as you run the blower thru all its speeds.

Larry

65GGvert

The fuse in the driver's foot panel marked "heater" is for the heater fan. The fan will not run with a blown fuse. The heater is hot coolant flowing through a core and is in no way electrical. Only the fan requires electrical power. The brown wire off the ignition is the source and then through the fuse marked "heater" directly to the brown wire on the fan switch. I believe the fuse you are showing is in the red wire that goes to the a/c relay.

Nowhere Man

Factory AC cars use a higher amp fuse in the fuse box for the heater slot then what's printed on the box.

A good reason for the fuse to blow for high speed blower would be the relay on the evaporater box

65GGvert

The wiring diagrams for 65 and 66 a/c cars still show 10a fuse in heater slot. I can't say I've ever pulled one and looked at the fuse rating.

Nowhere Man

I know 67 used a higher amped fuse in the heater spot I'm thinking a 15 or 20 It's in the owners manual.

Powershift

The 1967 Chevrolet Service Manual shows a 25 amp fuse in this slot. That sounds like a lot. I would double check this with the owners manual to confirm

30 amp fuse is shown for the in-line fuse to the blower.

Larry

Nowhere Man

Larry we should try and stay on target here do you have a 66 manual to see what goes in its fuse box

Powershift

Car is 1965. No, I don't have the 1965 Owners Manual or the 1965 Chevrolet Service Manual. But I know the owner does.

Larry

Kerouac

According to the 1965 Corvette Shop Manual:

"Two fuses are utilized in the Corvette Air Conditioning System.
1. System protection is provided by a 3 AG 20 fuse in the fuse panel attached to the passenger side of the firewall in front of the driver's seat.
2. High speed blower motor protection is provided by a 3 AG 30 in-line fuse located in the wiring over the evaporator case in the engine compartment."

My car is a 65 327/365 with factory air. Thanks again, gents.

Kerouac

I pulled the fuses in question. On the right side of the picture is the blown one from the fuse panel (what a PITA to get that out) and it is a 10 amp. Manual says it should be a 20.

On the left side of the picture is the in-line one from the the wiring above the evaporator case. It is a 25 amp and the manual says it should be a 30.

Maybe I've discovered the problem?

Nowhere Man

Very well could be. Cheap and easy enough to fix.

65GGvert

I'd be very watchful for a while after changing those fuses to a higher rating (even though it may be correct). If either fuse blows again, don't replace it until you find the problem. Or, if you replace them and the heater fan motor doesn't run properly at all speeds, turn it off and find out why. Hopefully it was a fluke, but that black powder inside the "heater" fuse shows a pretty fast blow, not just a melt.

TJefferson2020

Also, while you are at it, check your harness connections to the firewall behind the battery where the blower motor gets power - these get gummed up and loose (it should have a rubber boot on it - this boot hides the connection so you can't see if it is disconnected or loose.

Kerouac

Thanks to you knowledgable fellows the blower is blowing and the AC is running perfectly. It would appear that the problem was the fuse in the fuse panel for the heater (which controls the fan). A 10 amp was installed there, which is correct when the car is not equipped with AC. According to the Manual, when the car is equipped with AC a 20 amp fuse is required. I will keep an eye on things going forward. If I blow the 20amp fuse I will assume something more dire is afoot. Thanks again to each of you!

Powershift

When you get a chance on day, remove the two small screws and the blower motor resistor that is on the passenger side blower assembly in the engine compartment. AC cars should have 3-4 wire plug going to it and the words INDAK on the piece that is visible. The resistor(s) sit in the blower air stream to keep cool, but over time can get gummed up, corroded, broken, and/or covered with dirt. I will post up a pic in a few minutes. Unable to post pic due to difficulties, but see LICS Part # 35-47B.

I replaced the one on my 1967 car with a new INDAK one a few years ago. Just another thing to think about and occasionally service. Especially with an AC car.

Larry