Mia

I've searched the forums up and down, looked at schematics, wiring diagrams, and inside and out and cannot find this mysterious heater blower motor (in-line) fuse? Where is it? Anyone have any pictures? I have a 1979 L48 BTW. I've installed a new switch/thermostat control and nothing works. It did at one time, but the switch broke, or so I thought, so I replaced it.

I cannot for the life of me find the location of this "in-line" fuse under the hood, or anywhere else for that matter? Anyone?
Thanks.

Valic

well just some advice on my 79 l82 the heat/air wasnt workign and i thought it was the blower motor or soemthing first thing i went to look at was the relay under the hood and sure enough removed all the wires and they were corroded like crazy so i cleaned all the points and now its all working again so i dunno if you looked at the relay and made sure it was all set or not btu thats where i would start because it takes 5 minutes

...Roger...

A/C fuse is for the blower until you go to high and a high speed blower relay takes over,hs relay is fused by a fusible link at the starter.
The inline fuse was on earlier years.

Mia

Ok, that explains it. Thanks.
Fuse is fine.
Contacts on relay look fine.
Not sure about relay.
Either way I have NO speed of any kind at all.
Not sure where to look short of replacing the relay.

...Roger...

If you put power to the blower does it run, if so go out at the relay and put power with a jumper to the orange wire and see if the blower runs on high ? Leave the connector in place on the relay.

Mia

Tested the relay. It works. I ordered a new OEM one anyway. Its cheap and as long as I am replacing everything might as well do this too.

Time to test the blower motor now I guess. Its all that's really left.

...Roger...

Pull the connector off the relay and put a jumper between the red and the purple,blower should run. If it doesn't check the red for power.
Also make sure the blower metal case has a good ground,pay close attention to the ground spade,it uses a special screw. The other mounting screws go through the case into the fiberglass , the spade screw screws into the metal case grounding the spade to the case.
No ground , blower no worky.

Mia

I'll give that a shot. one quick question though. Does the gauge cluster need to be plugged in in order for the fan to work? I doubt it matters, but it is out at the moment. Thanks.

...Roger...

No , the cluster connector won't effect it.Just make sure the AC fuse is good.

Mia

Ok, I jumped the purple and red and the blower works. Power to red.

So to recap. Replaced fuse, relay, and switch and have power and blower works when jumped. Still have no low/med/high working from the switch when ignition is on.

Out of ideas.

...Roger...

Pull the 4 wire connector off the resistors and check the brown first. Then check the tan and lt bue with the switch in med and med-high.
If you don't have power on the brown go back and see if the AC fuse is blown.

Mia

By 4 wire connector do you mean the one in the engine compartment that goes to the AC housing? I put a test light on the brown to ground, then tan and blue to ground and got nothing. Ignition on and switch in med and med high. As for the AC fuse, which one is it. I have pulled and replaced every fuse in the fuse box 3 times now. Thanks.

Mia

FYI, AC fuse is fine. I am certain its the right fuse and location. Says A/C and is a 25 AMP

...Roger...

Yes thats the right connector
The AC fuse is above and to the right of the wiper fuse.

Mia

That's the one. Its fine. Replaced it again just in case. Still nothing. Damn gremlins.

I must be missing something really easy here.

I've replaced the fuse. I've replaced the relay. I've cleaned contacts, used dielectric grease, and replaced the entire C3 Corvette Heater Control Assembly.

I've double checked the connections on those too. pretty hard to mess that up. With the engine running when I adjusted the on/off, vent, ac, heat, etc, I can hear the vacuum so I believe that is engaging. Just no blower.

...Roger...

The brown needs to be hot with the key on,your going to have to go to the function switch (lever control ) and see if the brown is hot at that point.

Mia

If you mean the brown wire that goes to a connector that connects to the one that connects to the heater control inside the car under the console (if that makes sense) then, no, there is no power to it with ignition on.

...Roger...

Thats the one. That brown is fed from the AC fuse. So between the fuse and there, there is a disconnect. Wiring diagram shows a connector between the fuse box and the AC control. Follow the brown from the AC control towards the fuse box and see if you can find a connector.

...Roger...

Look close to the lighter on the drivers side of the console.

Mia

Did that. Also tested my test light on the lighter which works, so I know the test light and my grounding point was good.

I began following the brown wire back to the fuse box. I do see a larger connector under the dash that is mounted to the base of the steering column that it goes into. That looks good. I see a miriad of other crap and wires and connectors under there. Its a maze. Anyway, when I get more time this weekend I will take a look again.

My mechanic had been the last one under there fixing a vacuum leak, so perhaps he disconnected something by mistake. That would make more sense.
Thanks again for the help.