I have been chasing this problem for a year, I decided that today would be the day, Close, but not yet. (Sorry, but this is slightly complicated, I will do the best I can to describe everything I know as clearly as I can)

The blower has not worked since I got the car back on the road about a year ago. Looking at the diagram below-- there is no power on Point A (Blower resistor) or Point C (Heater Switch). There is also no continutiy between those two points. I can sometimes get continuity between Point B (Fuxe Box) and Point C (Heater Switch), but never between Point A (Blower Resistor) and Point B (Fuze Box).

Examining the fuze box carefully, the terminal for the fuze the side of the circuit disintegrated. I must conclude that the fuze connector has corroded and the wires have come disconnected behind the fuze block.

Fist question: Is there anyway to get to the back of the fuze block and make repairs -- I dont see how it would be possible unless one removed the wiring harness so that you could move the block.

So--- I decided to make a new circuit around the fuze block. Ran a 12AWG wire from the battery through a fuze, to point C (Heater switch) through the fire wall to Point B (Blower resistor). (Did anyone figure out what I did wrong?) Thats right!! The blower circuit has to be switched by the ignition because it is always on. I did prove that this fixes the problem, the blower works fine in all positions, exept for never turning off.

Question 2: How do I find a switched power souce that can handle 25Amps. Since the hot side of the fuze panel still seems ok, I will try to take it from there, but shoving a spade lug into the fuze box seems just to Bubba. (I realize this whole approach has a whole lot of bubba about it, but I cant see any other approach that does not remove the dash and wiring harness)

Sorry that it is so complicated, but any ideas would be appreciated

 

What year is the Corvette?

 

Sorry -- 1981

 

The blower is always supposed to run. LO speed always on so there is some circulation in the passenger compartment at all times.

 

If your 81 is the same as my 79 which I think it is your fuse box is held to the fire wall by two bolts/screws. You would have to release the engine side wiring harnesses which is held to the fuse box by one bolt/screw in the center on the engine compartment side. Then you can release the two bolts/screws on the fuse box and you should with some difficulty turn the fuse box around and get to the part you want. It is not the easiest project but has been done. The other possible solution is to take power from the back of the alternator inline fuse it with your 25amp fuse and then supply your rewire.

 

The un-bubba way would be to replace the engine and under-dash wiring harnesses with quality new units. IMO, the blower problem is a the start of many more electrical gremlins.

If the time and $ for that solution is too much ATM, you could put a relay & fuse at [51] that draws + from the hot side of the starter or alternator. Feed the blower switch across the switched side of the relay :

Bypass fuse at [50] with inline coupler
85 - connect to inline fuse A side
- connect inline fuse B side to [51] feed from Function Control Switch
86 - connect to ground
30 - connect to starter or alternator hot
87 - connect to [51] feed to blower switch

 

You need to pull the fusebox and repair the connections or replace the main harness bad connections cause FIRES! Have you ever seen a burned corvette or the garage it was parked in it's not pretty!!!!
Mark